Secure bi-directional network connectivity system between private networks

ABSTRACT

A secure private network connectivity system (SNCS) within a cloud service provider infrastructure (CSPI) is described that provides secure private network connectivity between external resources residing in a customer&#39;s on-premise environment and the customer&#39;s resources residing in the cloud. The SNCS provides secure private bi-directional network connectivity between external resources residing in a customer&#39;s external site representation and resources and services residing in the customer&#39;s VCN in the cloud without a user (e.g., an administrator) of the enterprise having to explicitly configure the external resources, advertise routes or set up site-to-site network connectivity. The SNCS provides a high performant, scalable, and highly available site-to-site network connection for processing network traffic between a customer&#39;s on-premise environment and the CSPI by implementing a robust infrastructure of network elements and computing nodes that are used to provide the secure site to site network connectivity.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related to application Ser. No. 17/515,087 filed onthe same day herewith, entitled “Transparent mounting of externalendpoints between private networks,” the entire contents of which areincorporated herein by reference for all purposes.

BACKGROUND

The demand for cloud-based services continues to increase rapidly. Theterm cloud service is generally used to refer to a service that is madeavailable to users or customers on demand (e.g., via a subscriptionmodel) using systems and infrastructure (cloud infrastructure) providedby a cloud services provider. Typically, the servers and systems thatmake up the cloud service provider's infrastructure are separate fromthe customer's own on-premise servers and systems. Customers can thusavail themselves of cloud services provided by a cloud service providerwithout having to purchase separate hardware and software resources forthe services. There are various different types of cloud servicesincluding Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS),Infrastructure-as-a-Service (IaaS), and others.

To take advantage of the numerous benefits provided by cloud services,an enterprise is often required to migrate on-premise applications anddata from their local data center to the public cloud infrastructure.This process typically requires the enterprise to set up a site-to-sitenetwork connection to establish secure connectivity between theiron-premise data center and the cloud infrastructure. Configuring a highperformant, scalable, and highly available site-to-site networkconnection to process network traffic between different networks can bea complex and time-consuming task for an enterprise especially when theenterprise's on-premises applications and data scale across multipledifferent networks.

BRIEF SUMMARY

The present disclosure relates generally to cloud-based services. Morespecifically, but not by way of limitation, the present disclosuredescribes a secure private network connectivity service within a cloudinfrastructure that includes improved capabilities to establish secureprivate bi-directional network connectivity between external resourcesresiding in a customer's on-premise environment and the customer'sresources residing in the cloud.

In certain embodiments, a secure network connectivity system isdisclosed. The secure network connectivity service enables secureprivate network connectivity between an on-premise network associatedwith a customer of the cloud service provider and a virtual cloudnetwork (VCN) hosted by the cloud service provider for the customer. Thesecure network connectivity system comprises a virtual overlay networkcomprising a set of one or more computing nodes. The system registers anexternal resource residing in the on-premise network as an externalendpoint in the virtual cloud network. The external endpoint isidentified by an Internet Protocol (IP) address in the virtual cloudnetwork. A first computing node in the set of computing nodes in thesystem creates an external resource representation for the externalendpoint in the virtual cloud network. The external resourcerepresentation is created by creating a virtual network interface card(VNIC) and assigning the Internet Protocol (IP) address associated withthe external endpoint to the VNIC. The first computing node thentransmits configuration information corresponding to the VNIC for theexternal resource representation to an agent configured in theon-premise network associated with the customer.

In certain examples, a second computing node in the set of computingnodes in the system receives a request for querying informationassociated with a resource residing in the VCN associated with thecustomer. The query is transmitted by the external resource residing inthe on-premise network. In certain implementations, the externalresource is provisioned with a logical interface. The second computingnode establishes a connection between the logical interface provisionedfor the external resource residing in the on-premise network and theVNIC created for the external resource representation in the virtualcloud network. The second computing node transmits the request to theresource residing in the virtual cloud network via the establishedconnection and obtains a result corresponding to the request via theestablished connection.

In certain embodiments, the agent in the on-premise network isconfigured to establish a secure Virtual Private Network (VPN)connection between the external resource residing in the on-premisenetwork and the set of one or more computing nodes comprising the securenetwork connectivity system. In certain examples, the agent isconfigured to provision the logical interface for the external resourceresiding in the on-premise network based at least in part on theconfiguration information corresponding to the VNIC for the externalresource representation. In certain examples, provisioning the logicalinterface for the external resource comprises, assigning, by the agent,the virtual Internet Protocol (IP) address of the virtual networkinterface card (VNIC) for the external resource representation to thelogical interface.

In certain examples, the configuration information corresponding to theVNIC for the external resource representation comprises the virtualInternet Protocol (IP) address of the VNIC, a fully qualified domainname associated with a computing instance associated with the VNIC and acloud identifier of the virtual cloud network associated with thecustomer.

In certain examples, the second computing node establishes theconnection between the logical interface provisioned for the externalresource residing in the on-premise network and the virtual networkinterface card created for the external resource representation in thevirtual cloud network via the agent residing in the on-premise network.

In certain examples, the second computing node transmits the request tothe resource residing in the virtual cloud network via the establishedconnection. This process involves, translating, by the second computingnode, the physical IP address associated with the external resource tothe virtual IP address associated with the VNIC for the externalresource representation in the virtual cloud network associated with thecustomer and transmitting the request to the virtual IP addressassociated with the VNIC.

In certain examples, the secure network connectivity system enablescreation of an external site representation of the on-premise networkassociated with the customer. The external site representation is alogical representation of the on-premise network and identified by anexternal site identifier and a customer identifier. In certain examples,the external resource is registered in the external site representation.

In certain examples, the second computing node in the secure networkconnectivity system establishes the connection between the logicalinterface provisioned for the external resource residing in the externalsite representation and the virtual network interface card created forthe external resource representation in the virtual cloud network. Incertain examples, the external resource is a database, an application,or a compute instance residing in the on-premise network.

Various embodiments are described herein, including methods, systems,non-transitory computer-readable storage media storing programs, code,or instructions executable by one or more processors, and the like.These illustrative embodiments are mentioned not to limit or define thedisclosure, but to provide examples to aid understanding thereof.Additional embodiments are discussed in the Detailed Description, andfurther description is provided there.

BRIEF DESCRIPTION

FIG. 1 depicts a distributed environment 100 that includes a secureprivate network connectivity service within a cloud service providerinfrastructure (CSPI), according to certain embodiments.

FIG. 2 depicts additional details of the operations performed by thesystems and subsystems shown in FIG. 1 for providing secure privatenetwork connectivity between a customer's external resource residing ina customer's on-premise network and resources and services residing inthe customer's VCN, according to certain embodiments.

FIG. 3 depicts an example of a process performed by the systems andsubsystems shown in FIG. 1 for providing secure private networkconnectivity, according to certain embodiments

FIG. 4 is a flowchart depicting a flow of network packets between anexternal resource residing in a customer's on-premise network and arepresentation of the external resource in the customer's virtual cloudnetwork, according to certain embodiments

FIG. 5 is a flowchart depicting the flow of network packets between anexternal resource representation in the customer's virtual cloud networkand an external resource residing in a customer's on-premise network,according to certain embodiments.

FIG. 6 is a high level diagram of a distributed environment showing avirtual or overlay cloud network hosted by a cloud service providerinfrastructure according to certain embodiments.

FIG. 7 depicts a simplified architectural diagram of the physicalcomponents in the physical network within CSPI according to certainembodiments.

FIG. 8 shows an example arrangement within CSPI where a host machine isconnected to multiple network virtualization devices (NVDs) according tocertain embodiments.

FIG. 9 depicts connectivity between a host machine and an NVD forproviding I/O virtualization for supporting multitenancy according tocertain embodiments.

FIG. 10 depicts a simplified block diagram of a physical networkprovided by a CSPI according to certain embodiments.

FIG. 11 is a block diagram illustrating one pattern for implementing acloud infrastructure as a service system, according to at least oneembodiment.

FIG. 12 is a block diagram illustrating another pattern for implementinga cloud infrastructure as a service system, according to at least oneembodiment.

FIG. 13 is a block diagram illustrating another pattern for implementinga cloud infrastructure as a service system, according to at least oneembodiment.

FIG. 14 is a block diagram illustrating another pattern for implementinga cloud infrastructure as a service system, according to at least oneembodiment.

FIG. 15 is a block diagram illustrating an example computer system,according to at least one embodiment.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, specificdetails are set forth in order to provide a thorough understanding ofcertain embodiments. However, it will be apparent that variousembodiments may be practiced without these specific details. The figuresand description are not intended to be restrictive. The word “exemplary”is used herein to mean “serving as an example, instance, orillustration.” Any embodiment or design described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother embodiments or designs.

The present disclosure relates generally to cloud-based services. Morespecifically, but not by way of limitation, the present disclosuredescribes a secure private network connectivity service within a cloudinfrastructure that includes improved capabilities to establish secureprivate bi-directional network connectivity between external resourcesresiding in a customer's on-premise environment and the customer'sresources residing in the cloud.

A cloud infrastructure can offer high-performance compute, storage, andnetwork capabilities in a flexible overlay virtual network that runs ontop of the physical underlay network and that is securely accessiblefrom an enterprise's on-premises network. The cloud infrastructureallows enterprises to manage their cloud-based workloads in the same waythey manage their on-premises workloads. Thus, enterprises can get allthe benefits of the cloud with the same control, isolation, security,and predictable performance as their on-premises network. An enterprisecan build their own networks using compute, memory, and networkingresources provided by the cloud. For example, a customer can useresources provided by the cloud to build one or multiple customizableand private network(s) referred to as virtual cloud networks (VCNs). Acustomer can deploy one or more customer resources, such as computeinstances, on these customer VCNs. Compute instances can take the formof virtual machines, bare metal instances, and the like. The cloud thusprovides infrastructure and a set of complementary cloud services thatenable enterprises (customers) to build and run a wide range ofapplications and services in a highly available hosted environment.

To take advantage of the numerous benefits provided by the cloudinfrastructure, many enterprises perform the migration of on-premiseapplications and data from their local data center to the public cloudinfrastructure. Migrating workloads from a local (i.e., on-premise) datacenter of an enterprise to the cloud can be a complex and challengingprocess. Common challenges encountered during cloud migration involveidentifying, by the enterprise, the type of migration to perform, thetype of resources that need to be moved, and data dependencies betweenthe resources. While migrating workloads, some resources (e.g.,databases, applications and the like) may need to reside at theon-premise data center for a certain period of time until they are ableto be successfully migrated into the cloud. Certain resources (e.g.,business-critical resources, resources that have data portabilityrestrictions or resources that have strict geographic requirements) maybe identified as resources that are not migrated to the cloud due tosecurity reasons and remain at the on-premise data center. For anenterprise to be able to securely access on-premise resources from theirVCN (in the cloud) and to enable resources residing in their on-premisedata center to be able to securely access resources residing in thecloud, secure private network connectivity needs to be establishedbetween the customer's (enterprise's) on-premise data center and thecustomer's VCN. Setting up a secure site-to-site network connection canbe a complex and time-consuming task for an enterprise. This typicallyrequires network policy level management, by a user (e.g., anadministrator) of the enterprise to set up the site-to-site network(e.g., VPN) connection, setting up multiple configuration parameters,setting up VPN components (e.g., a customer gateway device, a targetgateway device) for the site-to-site network connectivity and so on.

Additionally, in order to access a remote asset (e.g., an on-premiseresource such as a database or application) residing in their on-premisedata center from their VCN using the site-to-site network connection orfor remote assets residing in their on-premise data center to be able tosecurely access resources and services in the customer's VCN, the userof an enterprise has to perform additional tasks like manually configurethe gateway devices to perform route advertisements and network addresstranslations so that secure connectivity between remote assets in thecustomer's external environment and resources in the customer's VCN canbe achieved. The user also has to manually configure the remote asset inorder for traffic (e.g., network packets) to reach the remote asset fromthe customer's VCN and vice versa, configure route tables to include theroutes used by the site-to-site VPN connection, enable route propagationfor the route table to automatically propagate site-to-site VPN routes,update security rules and so on.

In certain embodiments, a secure private network connectivity servicewithin a cloud service provider infrastructure (CSPI) is described thatincludes improved capabilities to establish secure privatebi-directional network connectivity between external resources residingin a customer's on-premise environment and the customer's resourcesresiding in the cloud. The secure private network connectivity serviceis implemented using a secure network connectivity system (SNCS) withina cloud service provider infrastructure (CSPI). The SNCS described inthe present disclosure provides several technical advancements and/orimprovements over conventional cloud-based network connectivityservices. Using the disclosed new and improved architecture implementedby the SNCS, secure private bi-directional network connectivity betweenexternal resources residing in a customer's external site representationand resources and services residing in the customer's VCN in the cloudcan be achieved without a user (e.g., an administrator) of theenterprise having to explicitly configure the external resources,advertise routes or set up site-to-site network connectivity. The SNCSprovides a high performant, scalable, and highly available site-to-sitenetwork connection for processing network traffic between a customer'son-premise environment and the CSPI by implementing a robustinfrastructure of network elements and computing nodes that are used toprovide the secure site to site network connectivity. By using therobust infrastructure of network elements and computing nodesimplemented by the SNCS, a user of an enterprise can securely access itsexternal resources from the cloud as if they were connecting to anyother native resource within their VCN. Additionally, the SNCS enablesone or more external resources residing in a customer's on-premisenetwork to be able to securely reach out to and access resources andservices residing in the customer's VCN (i.e., cloud). The secureprivate bi-directional network connectivity between external resourcesin a customer's external site representation and resources and servicesresiding in the customer's VCN in the cloud can be achieved without auser (e.g., an administrator) of the enterprise having to explicitlyconfigure the external resources, advertise routes or set upsite-to-site network connectivity.

Referring now to the drawings, FIG. 1 depicts a distributed environment100 that includes a secure private network connectivity service within acloud service provider infrastructure (CSPI), according to certainembodiments. The distributed environment 100 includes multiple systemscommunicatively coupled to each other via one or more communicationnetworks. These communication networks may include public and privatenetworks. The distributed environment 100 depicted in FIG. 1 is merelyan example and is not intended to unduly limit the scope of claimedembodiments. Many variations, alternatives, and modifications arepossible. For example, in some implementations, the distributedenvironment depicted in FIG. 1 may have more or fewer systems orcomponents than those shown in FIG. 1 , may combine two or more systems,or may have a different configuration or arrangement of systems.

As shown in the example depicted in FIG. 1 , the distributed environment100 comprises a CSPI 102 that provides services and resources thatcustomers can subscribe to. In certain embodiments, the CSPI 102provides a secure private network connectivity service that includescapabilities to provide secure bi-directional private networkconnectivity between a customer's on-premise network and the customer'sVCN hosted by the CSPI 102. In the example shown in FIG. 1 , the secureprivate network connectivity service may be implemented by a securenetwork connectivity system (SNCS) 104 within the CSPI 102. The secureprivate network connectivity service provided by the SNCS 104 enablesone or more resources (also referred to herein as external resources orremote assets) residing in a customer's on-premise network to be able tosecurely access resources and services residing in the customer's VCN.The secure private network connectivity service provided by the SNCS 104additionally enables resources and services in the customer's VCN tosecurely access external resources residing in the customer's on-premisenetwork. A customer can access the external resources from within theirVCN as if they were connecting to any other native resource residing inthe customer's VCN. The secure access between the on-premise externalresources and the resources residing in the customer's VCN (i.e., cloud)can be enabled without requiring the customer (e.g., a user of theenterprise) to set an elaborate site-to-site network connection betweentheir on-premise network and the cloud, without the customer having tomake any changes to their external resources or without having thecustomer to configure routes to be used by the site-to-site connection.Additional details of the processing performed by the SNCS 104 to enablesecure bi-directional connectivity between external resources residingin the customer's on-premise network and the customer's resources andservices in the cloud are described in detail below.

In certain approaches, secure bi-directional connectivity between anexternal resource residing in a customer's on-premise network and thecustomer's resources and services in the cloud (e.g., the customer'sVCN) is achieved by the SNCS 104 using a multi-stage process. In a firststage, a user (e.g., an administrator) associated with the customer cancreate an “external site representation” 106 of the customer'son-premise network. For instance, the user may interact with the SNCS104 via a console user interface (UI) 108 of an application executed bya user device, via APIs or via a command line interface (CLI) executedby the user's device to create the external site representation 106. Anexternal site representation (e.g., 106) may represent a logical orvirtual representation of the customer's external site (e.g., on-premisenetwork/on-premise data center) and may be identified by an externalsite identifier and a tenant (customer) identifier. By way of example,an external site representation 106 may represent a high level containerresource that logically represents a portion of the customer'son-premise network and a subset of one or more external resourcesresiding in the on-premise network.

In a second stage, the user downloads an agent 112 andinstalls/configures the agent 112 in the external site representation106. In certain embodiments, the agent 112 may be a software applicationthat is downloaded by the user as part of a download package provided bythe SNCS 104 when the user subscribes to the secure private connectivityservices provided by the SNCS 104. The agent 112 may be installed andconfigured by the user in the external site representation 106 via theconsole UI 108.

In a third stage, upon successful installation of the agent 112 in theexternal site representation 106, the SNCS 104 authenticates the agent112 and orchestrates the setting up of a tenant-specific overlay network128 for the customer. The tenant-specific overlay network 128 mayrepresent a virtual overlay network that is built on top of a physicalnetwork by the SNCS 104 for each tenant (customer) who subscribes to theservices provided by the SNCS. The tenant-specific overlay network 128is used to establish secure private network connectivity between thecustomer's external site representation 106 and the customer's VCN 148in the CSPI. As shown in the embodiment depicted in FIG. 1 , thetenant-specific overlay network 128 may comprise a distributed andhorizontally scalable fleet of computing nodes that include a set of oneor more tunnel hosts (also referred to herein as tunnel virtualmachines), tunnel VM-1 116 and tunnel VM-2 122 and a set of one or moreresource hosts (also referred to herein as resource virtual machines),resource VM-1 130 and resource VM-2 132. A host (e.g., a tunnel host ora resource host) may be composed of a set of containers (also referredto herein as shards) that are inter-connected with each other in thetenant-specific overlay network 128. The tunnel VMs 116 and 122 are usedfor running per-tenant tunnel shards. For instance, as shown in FIG. 1 ,the tunnel VM-1 116 is used to run a tunnel shard 120 and the tunnelVM-2 122 is used to run a tunnel shard 126 for a specifictenant/customer of the CSPI. Each tunnel shard 120 or 126 is responsiblefor providing secure connectivity to the customer's external siterepresentation 106. The set of resource VMs 130 and 132 may be used forrunning per tenant resource shards. For instance, as shown in FIG. 1 ,the resource VM-1 130 is used to run a resource shard 136 and theresource VM-2 132 is used to run a resource shard 140 for thetenant/customer. A resource shard may be used to receive traffic fromthe customer's VCN and forward it to the customer's external siterepresentation. Additional details of the operations performed by thetunnel shards and the resource shards shown in FIG. 1 for providingsecure connectivity between the customer's external site representation106 and the customer's VCN 148 is described in detail in FIG. 1 .

Each tunnel VM (116, 122) and resource VM (130, 132) is additionallyconfigured with a host manager (118, 134) respectively. The hostmanagers (118, 134) represent processes executing on the tunnel VMs andthe resource VMs. The host managers (118 or 134) may implement API'sthat are used to create the tunnel and resource shards. In certainimplementations, the host managers (118, 134) may be stateless andoperate in an imperative mode (i.e., as a sequence of commands for thehost manager to perform) by receiving instructions from a user (via APIs108) regarding the type of shard (tunnel or resource shard) to becreated and the specific configuration of the shard. The host managersmay additionally be responsible for collecting and monitoring the statusof the tunnel shards and the resource shards.

After the SNCS 104 sets up the tenant-specific overlay network 128 forthe customer as described above, in a fourth stage, the user registersan on-premise asset (e.g., an external resource 114A) in the externalsite representation 106 as an external endpoint in their VCN. Theexternal resource 114A may represent an on-premise resource or assetsuch as a database, a computing instance, an application or the likeresiding in the customer's on-premise network that the customer intendsto establish secure bi-directional connectivity to, with resources andservices residing in the customer's VCN. To register the externalresource 114A, the user (via the console UI 108) identifies the externalresource (e.g., 114A) that is to be enabled secure private networkconnectivity from their VCN 148 and using the console UI 108 (or viaAPIs), registers the external resource as an external endpoint in theirVCN. As part of registering the external resource, the user providesconfiguration information related to the external resource such as theon-premise physical IP address associated with the external resource,the port number that the external resource is accessible at, and ahostname (or a fully qualified domain name (FQDN)) of the externalresource via the console UI or APIs provided by the SNCS. The user alsoselects a subnet in the customer's VCN where the external endpoint forthe external resource is to be created. The SNCS receives theconfiguration information and creates an external endpoint for theexternal resource in the customer's VCN. The external endpoint isidentified by an IP address, a port number and a FQDN (hostname) in thecustomer's VCN.

In a fifth stage, the SNCS 104 (via control plane APIs) then creates anexternal resource representation for the external endpoint in thecustomer's VCN. In a certain implementation, the creation of theexternal resource representation comprises creating a remote mount pointVNIC and assigning the IP address associated with the external endpointto the VNIC. The SNCS (via control plane APIs) then creates resourceshards on the resource VMs which are capable of logically attaching theVNIC (via a worker interface) to the resource shards.

In a sixth stage, the agent 112 downloads and reads the configurationinformation 156 associated with the VNIC 142 created for the externalresource representation 114A in the customer's VCN 148 and copies theconfiguration information 156 onto the registered external resource114A. The configuration information may include, for instance, thevirtual IP address of the VNIC, a fully qualified domain name associatedwith a computing instance associated with the VNIC and a cloudidentifier of the virtual cloud network associated with the customer.Using the configuration information 156, the agent 112creates/provisions a logical interface 158 for the external resource114A. The logical interface 158 may represent a software entityconsisting of an IP address. In a certain implementation, the creationor provisioning of the logical interface 158 by the agent 112 comprisesassigning, by the agent, the virtual IP address assigned to the VNIC 142created for the external resource representation to the logicalinterface 158.

Since the external resource 114A is provisioned with a logical interface158 that is assigned with the virtual IP address corresponding to theVNIC 142 for the external resource representation residing in thecustomer's VCN, the external resource now becomes part of the customer'sVCN and is able to securely access resources and services that are inthe cloud (e.g., in the customer's VCN 148) by using the secure privatenetwork connectivity services provided by the SNCS 104. For instance,the external resource 114A, via its logical interface 158, can securelyreach/access a compute instance 150 in the customer's VCN 148 or aservice 152 (e.g., a streaming service or an object storage service) inthe customer's VCN by establishing, via the agent 112, a connection tothe tunnel hosts in the SNCS 104. Similarly, a client application in thecustomer's VCN 148 can use the services provided by the SNCS 104 tosecurely access the external resource 114A in the customer's on-premisenetwork using the VNIC representation 142 of the external resource as ifthey were connecting to any other native resource in the customer's VCN148. In this manner, secure bi-directional connectivity between anexternal resource residing in a customer's on-premise network and thecustomer's resources and services in the cloud (e.g., the customer'sVCN) is achieved by the SNCS 104.

FIG. 2 depicts additional details of the operations performed by thesystems and subsystems shown in FIG. 1 for providing secure privatenetwork connectivity between a customer's external resource residing ina customer's on-premise network and resources and services residing inthe customer's VCN, according to certain embodiments. The systems andsubsystems depicted in FIG. 2 may be implemented using software (e.g.,code, instructions, program) executed by one or more processing units(e.g., processors, cores) of a computing system, hardware, orcombinations thereof. The software may be stored on a non-transitorystorage medium (e.g., on a memory device). The distributed environment200 depicted in FIG. 2 is merely an example and is not intended tounduly limit the scope of claimed embodiments.

Many variations, alternatives, and modifications are possible. Forexample, in some implementations, the distributed environment depictedin FIG. 2 may have more or fewer systems or components than those shownin FIG. 2 , may combine two or more systems, or may have a differentconfiguration or arrangement of systems. Inventors, we have describedthe system in FIG. 2 largely based on the system architecture (SNCS)described in invention 1 (IaaS 272.1). Please review the description onFIG. 2 below and add/edit it if required for more clarity.

As previously described in FIG. 1 , as part of the connection processimplemented by the SNCS 104 to provide secure private networkconnectivity between a customer's on-premise network and the customer'sVCN hosted by the CSPI 102, a user (e.g., an administrator) associatedwith the customer creates an “external site representation” (e.g., 106)of the customer's on-premise network, configures an agent (e.g., 112) inthe external site representation, registers an on-premise asset in theexternal site representation and creates a remote mount point (alsoreferred to herein as an endpoint) in the customer's VCN for theregistered external resource. Upon successful installation of the agent(e.g., 112) in the external site representation, the agent 112establishes a Virtual Private Network (VPN) connection (also referred toherein as a VPN tunnel) to the SNCS 104 via a public network (e.g.,Internet 110). The VPN connection is an encrypted connection between thecustomer's external site representation 106 and the customer's VCN 148.In a certain implementation, the VPN connection utilizes a securetunneling protocol (e.g., the Layer 2 Tunneling Protocol (L2TP)protocol) to establish secure private network connectivity to the SNCS104 via the Internet 110. When the agent 112 is installed in theexternal site representation 106, it starts a bootstrap process toactivate itself with the SNCS 104 by passing information such as acompartment identifier associated with the agent 112 and an externalsite representation identifier in a configuration file to the SNCS 104.When the agent 112 bootstraps itself, it communicates with the controlplane of the SNCS which starts the registration and activation process.During the activation process, the control plane sends back all therequired information (e.g., certificates, Public IP and the like) thatis needed by the gateway appliance to establish a secure tunnelconnection to the VPN server. The agent 112 then establishes secure VPNconnectivity to the SNCS 104 by executing a VPN client program whichopens a secure VPN tunnel connection to a VPN server installed at theSNCS. The secure tunnel terminates on a tunnel shard (e.g., 120) that isplaced on a tunnel VM (e.g., 116) in the SNCS 104.

In the specific implementation depicted in FIG. 1 , the agent 112 isconfigured with two VPN clients, VPN client-1 206 and VPN client-2 208that are each configured to establish tunnels that terminate on twodifferent VPN servers, VPN server-1 224 and VPN server-2 226 executingin tunnel shards, tunnel shard-1 120 and tunnel shard-2 126respectively. In the implementation depicted in FIG. 2 , every physicalinstallation of an agent 112 results in the establishment of two tunnelsand hence if one tunnel goes down, traffic (i.e., network packets) canautomatically be routed across the second tunnel. While the specificimplementation shown in FIG. 2 depicts two tunnels, in otherimplementations, the SNCS 104 may be configured to implement more thantwo redundant tunnels for every physical installation of the agent 112or may just implement a single tunnel upon installation of the agent112.

In certain embodiments, the agent 112 uses a standard exterior gatewayprotocol such as the Border Gateway Protocol (BGP) to establish BGPpeering sessions with the tunnel shards 120 and 126. Using BGP, theagent 112 exchanges routing and reachability information with the tunnelshards via a public interface 220 implemented within the agent 112. Aspart of the configuration information required for the BGP peeringsessions, the agent 112 injects its on-premise IP address into its localroute table 212 (also referred to herein as a routing information base(RIB)) which is received by the tunnel shards. The tunnel shards importthe routing information into their local route tables (228 and 236)after applying appropriate route filtering policies. The route filteringis needed to ensure that a compromised agent 112 does not injectarbitrary routes to the tunnel shards. In certain examples, the agent112 additionally comprises a routing manager 214. The routing manager214 may be implemented using an open source routing manager (e.g.,Zebra) that is part of a routing suite (e.g., Quagga). When the BGPpeering sessions learn routes and import them into its route table 212,the BGP peering sessions perform the best path calculation and use therouting manager 214 to add the best routes to the local kernel.

A tunnel shard (e.g., 120, 126) may be composed of a set of one or morecontainers. In certain implementations, a tunnel shard (120 or 126) maycomprise a shell container that may be used to set up various networkinterfaces that enable the tunnel shard to communicate with both theagent 112 and other shards (e.g., resource shards 136 and 140) that arepart of the tenant-specific overlay network 128. In the embodimentdepicted in FIG. 2 , the network interfaces implemented within a shellcontainer in a tunnel shard may include an external site interface(esi), a tunnel interface and a shard backend interface. For instance,the network interfaces implemented in tunnel shard-1 120 include atunnel interface 216, an external site interface 222 and a shard backendinterface 234. Similarly, the network interfaces implemented in tunnelshard-2 126 include a tunnel interface 218, an external site interface223 and a shard backend interface 235. A tunnel shard (e.g., 120 or 126)is additionally composed of a VPN server (224, 226) that is used toestablish a VPN tunnel to a VPN client (206, 208) executing in theexternal gateway appliance 112. An external site interface (222, 223)may be identified by a public IP that is known to the agent 112 on whichthe VPN client runs and is used to establish a tunnel to the tunnelshard. When the VPN client (e.g., 206, 208) connects to the VPN server(224, 226), a tunnel interface (216, 218) is created and placed in apre-configured VPN subnet of the tunnel shard.

In certain implementations, each tunnel shard (e.g., 120, 126) mayutilize the Border Gateway Protocol (BGP) to establish BGP peeringsessions between the external gateway appliance and the tunnel shardsand BGP peering sessions between the tunnel shards and the resourceshards. The BGP peering sessions are used to exchange routing andreachability information with the resource shards via the shard backendinterfaces (234, 235) and to exchange routing and reachabilityinformation with the external site representation 106 via the externalsite interfaces (222, 223). As part of the configuration informationrequired for the BGP peering sessions, an IP address that identifies thetenant-specific overlay network 128 is added to the route tables 228,236 (i.e., routing information bases (RIBs)) implemented in the tunnelshards 120, 126 respectively. In a certain implementation, the ClasslessInter-Domain Routing (CIDR) technique may be used for allocating the IPaddress to the tenant-specific overlay network. The route tables (228,236) list the routes to particular network destinations such as to theresource shards (136, 140) and to the external site representation 106.In some cases, the route tables (228, 236) also list metrics (distances)associated with those routes. When the BGP peering sessions with theresource shards are established, the route in the route tables ispropagated to the resource shards. As shown in FIG. 2 , each tunnelshard (120, 126) additionally comprises a routing manager (228, 240).The routing manager (228 or 240) may be implemented in a similar mannerto the routing manager (214) implemented in the external gatewayappliance 112. When BGP learns routes and imports them into the routetables in the tunnel shards, it performs the best path calculation anduses the routing manager to push the best routes to the external siterepresentation 106 and to the resource shards 136, 140.

A resource shard (136, 140) may be composed of a set of containers. Incertain implementations, a resource shard (136, 140) may comprise ashell container that may be used to set up a virtual tunnel endpointVTEP (242, 243) with the tunnel shards (116, 126). Each resource shard(136, 140) may use BGP to establish peering sessions with the tunnelshards and to exchange routing and reachability information with thetunnel shards via the virtual tunnel endpoints (242, 243). A resourceshard (136, 140) additionally comprises a routing manager (250, 260)that is configured to perform the same functionality as the routingmanager (232 or 240) implemented in the tunnel shards. Each resourceshard (136, 140) additionally includes a proxy server (244, 254). Theproxy servers (244 or 254) may be configured to accept connections froma client application 144 in the customer's VCN 148 and initiate newconnections to the external resource in the external siterepresentation.

In certain implementations, for every registered external endpoint(i.e., corresponding to an external resource in the external siterepresentation), a unique proxy server container is launched andattached to a resource shard. When registering the external resource andcreating a remote mount point VNIC for the registered external endpointin the customer's VCN, a user may provide configuration information suchas the IP address of the external resource, the port number of theexternal resource, and the name of the external resource to the SNCS104. This configuration information is provisioned in the proxy serversand used by a client application in the customer's VCN to connect to theexternal resource. When the external resource is successfully registeredas an external endpoint in the customer's VCN by the SNCS, the SNCS 104(via control plane APIs) creates a VNIC and assigns the IP addressassociated with the external endpoint to the VNIC.

In the example depicted in FIG. 2 , the registered external endpoint(i.e., external resource in the external site representation) representsa database 202 residing in the external site representation 106. Theproxy servers (244, 254) listen on the virtual IP address assigned tothe VNIC 206 that is created for the registered external endpoint 202.This ensures that the same VNIC IP cannot be used to access otherregistered external resources in the external site representation. Whena client application 144 running in the customer's VCN receives a queryto obtain information stored in the external database 202, it transmitsnetwork packets to the VNIC IP in the customer's VCN. The networkpackets are received by worker VNICs (251, 252) that are attached to theresource shards (136, 140). The worker VNICs are configured with thevirtual IP address of the VNIC and in turn, initiate a connection to theregistered external resource in the external site representation via theproxy servers (244, 254). The proxy severs (244, 254) perform a networkaddress translation (NAT) to translate the virtual IP address assignedto the VNIC 206 to the real/physical IP address of the external resource114A.in the external site representation 106. The resource shards (136,140) using the proxy servers (244, 254) initiate a connection to theagent 112 via the tunnel shards (120, 126). The agent 112 receives thenetwork packets from the tunnel shards (120, 126) and, in turn, routesthe packets to the registered external resource (i.e., database 202) inthe external site representation 106. The proxy servers (244, 254)additionally include capabilities to load-balance the network traffic tothe external resource across the tunnel shards. In certain embodiments,the proxy servers (244, 254) may be configured to multiplex connectionsfrom multiple client applications onto a single connection towards theexternal site representation.

In a similar manner, a registered external resource (i.e., database 202)residing in the external site representation 106 can reach out to andsecurely access a resource (e.g., compute instance 150) or a service(e.g., private endpoint VNIC 152) residing in the customer's VCN. Aspreviously described in FIG. 1 , the agent 112 creates/provisions alogical interface 204 for the external resource 202. By creating alogical interface 158 for the external resource 114A and assigning thevirtual IP address of the VNIC representation 206 of the database 202 tothe logical interface, the database 202(which resides in the customer'son-premise network) is able to securely access a compute instance 150 inthe customer's VCN 148 or a service 156 (e.g., a streaming service or anobject storage service in the CSPI) via a private endpoint VNIC 142 inthe customer's VCN 148 using the secure private network connectivityservices provided by the SNCS 104. For instance, in the embodimentdepicted in FIG. 2 , the agent 112 can receive a query from the database202 requesting information associated with a resource (e.g., 150) in thecustomer's VCN. The agent 112 then transmits network packetscorresponding to the query to the tunnel shards (120, 126). The tunnelshards, in turn, initiate a connection to the resource shards (136,140). The proxy severs (244, 254) in the resource shards (136, 140)perform a network address translation (NAT) to translate the real IPaddress of the external resource in the external site representation 106to the virtual IP address of the VNIC representation 206 of the externalresource (e.g., database 202) in the customer's VCN. The worker VNICs(251, 252) that are attached to the resource shards (136, 140) in turn,initiate a connection to the VNIC representation 206 of the database 202in the customer's VCN which transmits the network packets correspondingto the query to the requesting resource (e.g., 150) in the customer'sVCN. In this manner, the SNCS 104 ensures that secure privatebi-directional network connectivity is established between an externalresource (e.g., database 202) residing in a customer's on-premisenetwork and resources (e.g., 150) and services (e.g., 152) in thecustomer's VCN (i.e., cloud).

In certain implementations, the registered external endpoint thatrequires private connectivity from the customer's VCN 148 may beimplemented as a Service VNIC, also referred to herein as an “SVNIC” inthe customer's VCN 148. The SVNIC may be implemented by the CSPI 102using a VNIC as a service (VNICaaS) system (not shown in FIG. 2 ) whichmay represent a horizontally scalable service implemented by the CSPI102 that is capable of hosting multiple VNICs (e.g., service VNIC 254)to process and transmit traffic between virtual cloud networks.Specifically, the VNICaaS is a virtual networking feature that enables aVNIC to be represented or used as a service (i.e., SVNIC). The VNICaaSprovides functionality of a VNIC without requiring a specific SmartNICor host of a compute instance within a virtual network to host the VNIC.Techniques used to represent registered endpoints as SVNICs have beendescribed in detail U.S. patent application Ser. No. 17/175,573,entitled “Techniques for high performant virtual routing capabilities.”The techniques described in U.S. patent application Ser. No. 17/175,573are merely meant as examples and are not intended to be limiting.Various other techniques may also be used to represent registeredendpoints and to process and transmit traffic between virtual cloudnetworks in alternative embodiments. Since an SVNIC is created for everyregistered external endpoint (e.g., database 202), a flexible number ofworkers can be configured per SVNIC. In a specific implementation, everySVNIC may be associated with two worker VNICs (e.g., 251, 252) that areattached to the different resource shards (e.g., 136, 140). The workerVNICs are passed into the resource shards and configured with the SVNICIP.

In the specific implementation depicted in FIG. 2 , a single agent 112is installed in the external site representation 106 and is configuredto establish two tunnels resulting in a total of two tunnel shards thatneed to be placed on the tunnel fleet implemented by the SNCS 104. For afixed number of tunnel shards as described in this implementation, everyresource shard may be pre-configured with a fixed set of BGP peers alongwith static Address Resolution Protocol (ARP) entries for those peers.In certain approaches, the BGP container on the tunnel shard may beconfigured with a “Dynamic BGP peer” in which a CIDR block of IPaddresses can be specified from where BGP can accept incomingconnections. This CIDR block may be set to the CIDR of thetenant-specific overlay network and hence as the resource shardsgrow/shrink the BGP peers on the tunnel shard also change appropriately.From the perspective of the resource shards, every resource shard nowhas two BGP peering connections and since each of the BGP peerspropagate the same CIDR route to the on-premise network that it learnsfrom the external site representation, every resource shard has twoequal-cost paths towards the on-premise network. Similarly from theexternal gateway's perspective, the agent 112 establishes two tunnelstowards the SNCS 104 and the tunnel shards advertise the tenant-specificoverlay network routes to the agent 112 which then installs theappropriate route to the tenant-specific overlay network.

Using the disclosed new and improved architecture implemented by theSNCS 104, secure private bi-directional network connectivity betweenexternal resources in a customer's external site representation andresources and services residing in the customer's VCN in the cloud canbe achieved without a user (e.g., an administrator) of the enterprisehaving to explicitly configure the external resource, advertise routesor set up site-to-site network connectivity. The SNCS 104 provides ahigh performant, scalable, and highly available site-to-site networkconnection for processing network traffic between a customer'son-premise environment and the CSPI by implementing a robustinfrastructure of network elements and computing nodes (i.e., atenant-specific overlay network 128) for each tenant/customer that usesthe services provided by the SNCS 104. The tunnel hosts in thetenant-specific overlay network 128 are used to provide secureconnectivity to the customer's external site representation 106 and theresource hosts are used to receive traffic from the customer's VCN andforward it to the customer's external site representation. The resourcehosts are additionally capable of receiving traffic from an externalresource in the external site representation and forward it to resourcesor services residing in the customer's VCN. By using the robustinfrastructure of network elements and computing nodes implemented bythe tenant-specific overlay network, an enterprise can securely accessits external resources from the cloud as if they were connecting to anyother native resource within their VCN. A user of the enterprise canaccess its external resources without setting an elaborate site-to-sitenetwork between their on-premise network and the cloud, without makingany changes to their external resources and without configuring routesto be used by the site-to-site connection. Similarly, by creating alogical interface for the external resource and associating the logicalinterface with the virtual IP address of the VNIC representation of theexternal resource, the external resource (which resides in thecustomer's on-premise network) is able to securely access resources andservices that are in the cloud (e.g., in the customer's VCN 148) usingthe secure private network connectivity services provided by the SNCS104.

FIG. 3 depicts an example of a process performed by the systems andsubsystems shown in FIG. 1 for providing secure private networkconnectivity, according to certain embodiments. The processing depictedin FIG. 3 may be implemented in software (e.g., code, instructions,program) executed by one or more processing units (e.g., processors,cores) of the respective systems, hardware, or combinations thereof. Thesoftware may be stored on a non-transitory storage medium (e.g., on amemory device). The process 300 presented in FIG. 3 and described belowis intended to be illustrative and non-limiting. Although FIG. 3 depictsthe various processing steps occurring in a particular sequence ororder, this is not intended to be limiting. In certain alternativeembodiments, the steps may be performed in some different order or somesteps may also be performed in parallel. In certain embodiments, such asin the embodiment depicted in FIG. 1 , the processing depicted in FIG. 3may be performed by the computing nodes (e.g., 116, 122, 130 and 132)comprising the tenant-specific overlay network 128.

The processing depicted in FIG. 3 assumes that a user (e.g., anadministrator) associated with the customer has created an external siterepresentation (e.g., 106) of the customer's on-premise network and hasconfigured an agent (e.g., 112) in the external site representation 106.The processing depicted in FIG. 4 further assumes that the SNCS 104 hasauthenticated the agent 112 and has configured/established atenant-specific overlay network (e.g., 128) comprising a distributed andhorizontally scalable fleet of computing nodes for the customer. Asdescribed in FIG. 1 , the set of one or more computing nodes includeresource hosts (i.e., resource virtual machines, 130, 132) and tunnelhosts (i.e., tunnel virtual machines, 116, 122).

The processing depicted in FIG. 3 may be initiated at block 302 when theSNCS 104 executes the tenant-specific overlay network (e.g., 128)comprising a distributed and horizontally scalable fleet of computingnodes. The tenant-specific overlay network is used to establish secureprivate network connectivity between the customer's external siterepresentation and the customer's VCN (e.g., 148) in the CSPI.

At block 304, the SNCS (via control plane APIs) registers an externalresource residing in the customer's on-premise network as an externalendpoint in the customer's VCN. The external endpoint is identified byan IP address in the customer's VCN. As previously described, theexternal resource may represent a database, a computing instance, or anapplication in the external site representation 106 that the customerintends to enable secure bi-directional private network connectivityfrom within their VCN. As part of registering the external resource, auser of the SNCS provides configuration information related to theexternal resource such as the on-premise physical IP address associatedwith the external resource, the port number that the external resourceis accessible at, and a hostname (or a fully qualified domain name(FQDN)) of the external resource via the console UI or APIs. The useralso selects a subnet in the customer's VCN where the external endpointfor the external resource is to be created. Based on the configurationinformation, the SCNS creates an external endpoint for the externalresource in the customer's VCN. The external endpoint is identified byan IP address, a port number and a FQDN (hostname) in the customer'sVCN.

At block 306, a first computing node (e.g., a resource VM 130 orresource VM 132) in the SNCS creates an external resource representationfor the external endpoint in the customer's VCN. In a certainimplementation, the creation of an external resource representationinvolves creating, by the first computing node, a VNIC and assigning theIP address of the external endpoint to the VNIC.

At block 308, the first computing node transmits configurationinformation corresponding to the VNIC created for the external resourcerepresentation in the customer's VCN to the agent 112 configured in theon-premise network. As part of the processing performed in block 308,the agent 112 downloads and copies the configuration information ontothe registered external resource residing in the on-premise network. Aspreviously described, the configuration information may include, forinstance, the virtual IP address of the VNIC, a fully qualified domainname associated with a computing instance associated with the VNIC and acloud identifier of the virtual cloud network associated with thecustomer. Using the configuration information, the agent 112creates/provisions a logical interface (e.g., 158) for the externalresource (e.g., 114A). In a certain implementation, the creation orprovisioning of the logical interface by the agent 112 comprisesassigning, by the agent, the virtual IP address assigned to the VNIC 142created for the external resource representation to the logicalinterface 158 provisioned for the external resource 114A.

At block 310, a second computing node (e.g., a tunnel VM 116 or tunnelVM 122) receives a request for querying information associated with aresource (e.g., compute instance 150) residing in the customer's VCN. Incertain examples, the request may be transmitted by the externalresource (e.g., 114A) residing in the on-premise network, via itslogical interface 158. For instance, a user associated with the customermay transmit (e.g., via the UI 108), a request for querying informationassociated with the compute instance 150 residing in the customer's VCNto the external resource residing in the customer's on-premise network.The external resource may, in turn, may transmit the query to the agent112 residing in the on-premise network. The agent 112 receives the queryrequest and transmits network packets corresponding to the query requestto the tunnel shards (120 or 126) running in the tunnel VMs.

At block 312, the second computing node (e.g., a tunnel VM 116 or tunnelVM 122) establishes a connection between the logical interfaceprovisioned for the external resource and the VNIC created for theexternal resource representation in the customer's VCN via a resourceshard (e.g., 136 or 140). In a specific implementation, the tunnelshards (e.g., 120 or 126) may include capabilities to translate thereal/physical IP address assigned to the external resource to thevirtual IP address of the VNIC 142 and initiate a connection to the VNIC142 via the resource shards (136 or 140). The resource shards, in turn,initiate a connection to the resource (e.g., 150) in the customer's VCN.

At block 314, the second computing node (e.g., a tunnel VM 116 or tunnelVM 122) transmits the request to the resource residing in the customer'sVCN via the connection established in block 410. At block 412, thesecond computing node obtains a result corresponding to the request viathe established connection. The result is then transmitted to theexternal resource residing in the external site representation via theagent 112. For example, if the resource is a database executing in thecustomer's VCN, the result may include information stored in one or moretables in the database.

FIG. 4 is a flowchart depicting a flow of network packets between anexternal resource residing in a customer's on-premise network and arepresentation of the external resource in the customer's virtual cloudnetwork, according to certain embodiments. The processing depicted inFIG. 4 may be implemented in software (e.g., code, instructions,program) executed by one or more processing units (e.g., processors,cores) of the respective systems, hardware, or combinations thereof. Thesoftware may be stored on a non-transitory storage medium (e.g., on amemory device). The process 400 presented in FIG. 4 and described belowis intended to be illustrative and non-limiting. Although FIG. 4 depictsthe various processing steps occurring in a particular sequence ororder, this is not intended to be limiting. In certain alternativeembodiments, the steps may be performed in some different order or somesteps may also be performed in parallel. In certain embodiments, such asin the embodiment depicted in FIG. 2 , the processing depicted in FIG. 4may be performed by the computing nodes (e.g., 116, 122, 130 and 132)comprising the tenant-specific overlay network 128.

The processing depicted in FIG. 4 may be initiated at block 402 when anexternal resource (e.g., a database 202) residing in the customer'son-premise network (i.e., the customer's external site representation106) receives a query for information associated with a resource (e.g.,150) residing in the customer's VCN (e.g., 148). As previouslydescribed, a user associated with the customer may transmit (e.g., viathe UI 108), a request for querying information associated with thecompute instance 150 residing in the customer's VCN to the externalresource residing in the customer's on-premise network. The externalresource may, in turn, may transmit the query to the agent 112 residingin the on-premise network.

At block 404, the agent 112 receives the query and transmits networkpackets corresponding to the query to the tunnel shards (120 or 126)running in the tunnel VMs. In certain examples, as part of theprocessing performed in block 404, the agent 112 may encrypt the networkpackets prior to transmitting the network packets to the tunnel shards.

At block 406, the tunnel shards receive the encrypted network packetsand transmit the encrypted network packets to the resource shards (136,140) running in the resource VMs. Specifically, and as shown in FIG. 2 ,the encrypted network packets may be received by worker VNICs (251, 252)that are attached to the resource shards (136, 140).

At block 408, the resource shards (136, 140) decrypt the network packetsand perform a network address translation (NAT) to translate thephysical IP address assigned to the external resource to the virtual IPaddress of the VNIC (e.g., 206) that is associated with the externalresource representation in the customer's VCN.

At block 410, the resource shards (136, 140) transmit the networkpackets to the VNIC created for the external resource representation inthe customer's VCN.

At block 412, the VNIC transmits the network packets corresponding tothe query to the resource (e.g., 150) residing the customer's VCN.

FIG. 5 is a flowchart depicting the flow of network packets between anexternal resource representation in the customer's virtual cloud networkand an external resource residing in a customer's on-premise network,according to certain embodiments. The processing depicted in FIG. 5 maybe implemented in software (e.g., code, instructions, program) executedby one or more processing units (e.g., processors, cores) of therespective systems, hardware, or combinations thereof. The software maybe stored on a non-transitory storage medium (e.g., on a memory device).The process 500 presented in FIG. 5 and described below is intended tobe illustrative and non-limiting. Although FIG. 5 depicts the variousprocessing steps occurring in a particular sequence or order, this isnot intended to be limiting. In certain alternative embodiments, thesteps may be performed in some different order or some steps may also beperformed in parallel. In certain embodiments, such as in the embodimentdepicted in FIG. 2 , the processing depicted in FIG. 5 may be performedby the computing nodes (e.g., 116, 122, 130 and 132) comprising thetenant-specific overlay network 128.

The processing depicted in FIG. 5 may be initiated at block 502 when aclient application (e.g., 144) in the customer's VCN receives a queryfor information associated with an external resource (e.g., 202)residing in the customer's on-premise network (i.e., the customer'sexternal site representation 106). For instance, the query may bereceived from a user associated with the customer via the clientapplication. As part of the processing performed in block 502, theclient application 144 initiates a connection to the VNIC (e.g., 206)associated with the external resource representation by transmittingnetwork packets corresponding to the query to the virtual IP addressassigned to the VNIC in the customer's VCN.

At block 504, the client application transmits the network packetscorresponding to the query to the resource shards (136 or 140) runningin the resource VMs in the SNCS. Specifically, and as shown in FIG. 2 ,the network packets may be received by worker VNICs (251, 252) that areattached to the resource shards (136, 140). The proxy severs (244, 254)in the resource shards (136, 140) perform a network address translation(NAT) to translate the virtual IP address assigned to the VNIC to thephysical IP address of the external resource in the external siterepresentation 106 and initiate a connection to the agent 112 via thetunnel shards (120, 126).

At block 506, the resource shards transmit the network packets to thetunnel shards (120, 126). As part of the processing performed in block506, the tunnel shards may encrypt the network packets received from theresource shards prior to transmitting the packets to the agent 112 inthe external site representation 106.

At block 508, the tunnel shards transmit the network packets to theagent 112 residing in the customer's external site representation. Aspart of the processing performed in block 508, the agent 112 decryptsthe network packets prior to transmitting the network packets to theexternal resource (e.g., 202) in the external site representation (e.g.,106).

At block 510, the agent 112 transmits the network packets to theexternal resource (e.g., 202) residing in the customer's external siterepresentation. The external resource receives the network packetscorresponding to the query and generates response network packetscorresponding to the query. The response network packets may then betransmitted by the external resource back to the client application. Forexample, as part of a response network packet flow, network packetscorresponding to a response to the query are transmitted from theexternal resource to the agent. The agent encrypts the network packetsand transmits the encrypted network packets to the tunnel shards. Thetunnel shards receive the encrypted packets and transmit the packets tothe resource shards. The resource shards decrypt the network packets andperform a reverse network address translation (NAT) to translate thephysical/real IP address assigned to the external resource to thevirtual IP address of the VNIC that is associated with the externalresource representation in the customer's VCN. The resource shards thentransmit the response network packets to the VNIC which in turntransmits the response packets to the requesting client application 144in the customer's VCN 148.

Example Virtual Networking Architecture

The term cloud service is generally used to refer to a service that ismade available by a cloud services provider (CSP) to users or customerson demand (e.g., via a subscription model) using systems andinfrastructure (cloud infrastructure) provided by the CSP. Typically,the servers and systems that make up the CSP's infrastructure areseparate from the customer's own on-premise servers and systems.Customers can thus avail themselves of cloud services provided by theCSP without having to purchase separate hardware and software resourcesfor the services. Cloud services are designed to provide a subscribingcustomer easy, scalable access to applications and computing resourceswithout the customer having to invest in procuring the infrastructurethat is used for providing the services.

There are several cloud service providers that offer various types ofcloud services. There are various different types or models of cloudservices including Software-as-a-Service (SaaS), Platform-as-a-Service(PaaS), Infrastructure-as-a-Service (IaaS), and others.

A customer can subscribe to one or more cloud services provided by aCSP. The customer can be any entity such as an individual, anorganization, an enterprise, and the like. When a customer subscribes toor registers for a service provided by a CSP, a tenancy or an account iscreated for that customer. The customer can then, via this account,access the subscribed-to one or more cloud resources associated with theaccount.

As noted above, infrastructure as a service (IaaS) is one particulartype of cloud computing service. In an IaaS model, the CSP providesinfrastructure (referred to as cloud services provider infrastructure orCSPI) that can be used by customers to build their own customizablenetworks and deploy customer resources. The customer's resources andnetworks are thus hosted in a distributed environment by infrastructureprovided by a CSP. This is different from traditional computing, wherethe customer's resources and networks are hosted by infrastructureprovided by the customer.

The CSPI may comprise interconnected high-performance compute resourcesincluding various host machines, memory resources, and network resourcesthat form a physical network, which is also referred to as a substratenetwork or an underlay network. The resources in CSPI may be spreadacross one or more data centers that may be geographically spread acrossone or more geographical regions. Virtualization software may beexecuted by these physical resources to provide a virtualizeddistributed environment. The virtualization creates an overlay network(also known as a software-based network, a software-defined network, ora virtual network) over the physical network. The CSPI physical networkprovides the underlying basis for creating one or more overlay orvirtual networks on top of the physical network. The physical network(or substrate network or underlay network) comprises physical networkdevices such as physical switches, routers, computers and host machines,and the like. An overlay network is a logical (or virtual) network thatruns on top of a physical substrate network. A given physical networkcan support one or multiple overlay networks. Overlay networks typicallyuse encapsulation techniques to differentiate between traffic belongingto different overlay networks. A virtual or overlay network is alsoreferred to as a virtual cloud network (VCN). The virtual networks areimplemented using software virtualization technologies (e.g.,hypervisors, virtualization functions implemented by networkvirtualization devices (NVDs) (e.g., smartNICs), top-of-rack (TOR)switches, smart TORs that implement one or more functions performed byan NVD, and other mechanisms) to create layers of network abstractionthat can be run on top of the physical network. Virtual networks cantake on many forms, including peer-to-peer networks, IP networks, andothers. Virtual networks are typically either Layer-3 IP networks orLayer-2 VLANs. This method of virtual or overlay networking is oftenreferred to as virtual or overlay Layer-3 networking. Examples ofprotocols developed for virtual networks include IP-in-IP (or GenericRouting Encapsulation (GRE)), Virtual Extensible LAN (VXLAN-IETF RFC7348), Virtual Private Networks (VPNs) (e.g., MPLS Layer-3 VirtualPrivate Networks (RFC 4364)), VMware's NSX, GENEVE (Generic NetworkVirtualization Encapsulation), and others.

For IaaS, the infrastructure (CSPI) provided by a CSP can be configuredto provide virtualized computing resources over a public network (e.g.,the Internet). In an IaaS model, a cloud computing services provider canhost the infrastructure components (e.g., servers, storage devices,network nodes (e.g., hardware), deployment software, platformvirtualization (e.g., a hypervisor layer), or the like). In some cases,an IaaS provider may also supply a variety of services to accompanythose infrastructure components (e.g., billing, monitoring, logging,security, load balancing and clustering, etc.). Thus, as these servicesmay be policy-driven, IaaS users may be able to implement policies todrive load balancing to maintain application availability andperformance. CSPI provides infrastructure and a set of complementarycloud services that enable customers to build and run a wide range ofapplications and services in a highly available hosted distributedenvironment. CSPI offers high-performance compute resources andcapabilities and storage capacity in a flexible virtual network that issecurely accessible from various networked locations such as from acustomer's on-premises network. When a customer subscribes to orregisters for an IaaS service provided by a CSP, the tenancy created forthat customer is a secure and isolated partition within the CSPI wherethe customer can create, organize, and administer their cloud resources.

Customers can build their own virtual networks using compute, memory,and networking resources provided by CSPI. One or more customerresources or workloads, such as compute instances, can be deployed onthese virtual networks. For example, a customer can use resourcesprovided by CSPI to build one or multiple customizable and privatevirtual network(s) referred to as virtual cloud networks (VCNs). Acustomer can deploy one or more customer resources, such as computeinstances, on a customer VCN. Compute instances can take the form ofvirtual machines, bare metal instances, and the like. The CSPI thusprovides infrastructure and a set of complementary cloud services thatenable customers to build and run a wide range of applications andservices in a highly available virtual hosted environment. The customerdoes not manage or control the underlying physical resources provided byCSPI but has control over operating systems, storage, and deployedapplications; and possibly limited control of select networkingcomponents (e.g., firewalls).

The CSP may provide a console that enables customers and networkadministrators to configure, access, and manage resources deployed inthe cloud using CSPI resources. In certain embodiments, the consoleprovides a web-based user interface that can be used to access andmanage CSPI. In some implementations, the console is a web-basedapplication provided by the CSP.

CSPI may support single-tenancy or multi-tenancy architectures. In asingle tenancy architecture, a software (e.g., an application, adatabase) or a hardware component (e.g., a host machine or a server)serves a single customer or tenant. In a multi-tenancy architecture, asoftware or a hardware component serves multiple customers or tenants.Thus, in a multi-tenancy architecture, CSPI resources are shared betweenmultiple customers or tenants. In a multi-tenancy situation, precautionsare taken and safeguards put in place within CSPI to ensure that eachtenant's data is isolated and remains invisible to other tenants.

In a physical network, a network endpoint (“endpoint”) refers to acomputing device or system that is connected to a physical network andcommunicates back and forth with the network to which it is connected. Anetwork endpoint in the physical network may be connected to a LocalArea Network (LAN), a Wide Area Network (WAN), or other type of physicalnetwork. Examples of traditional endpoints in a physical network includemodems, hubs, bridges, switches, routers, and other networking devices,physical computers (or host machines), and the like. Each physicaldevice in the physical network has a fixed network address that can beused to communicate with the device. This fixed network address can be aLayer-2 address (e.g., a MAC address), a fixed Layer-3 address (e.g., anIP address), and the like. In a virtualized environment or in a virtualnetwork, the endpoints can include various virtual endpoints such asvirtual machines that are hosted by components of the physical network(e.g., hosted by physical host machines). These endpoints in the virtualnetwork are addressed by overlay addresses such as overlay Layer-2addresses (e.g., overlay MAC addresses) and overlay Layer-3 addresses(e.g., overlay IP addresses). Network overlays enable flexibility byallowing network managers to move around the overlay addressesassociated with network endpoints using software management (e.g., viasoftware implementing a control plane for the virtual network).Accordingly, unlike in a physical network, in a virtual network, anoverlay address (e.g., an overlay IP address) can be moved from oneendpoint to another using network management software. Since the virtualnetwork is built on top of a physical network, communications betweencomponents in the virtual network involves both the virtual network andthe underlying physical network. In order to facilitate suchcommunications, the components of CSPI are configured to learn and storemappings that map overlay addresses in the virtual network to actualphysical addresses in the substrate network, and vice versa. Thesemappings are then used to facilitate the communications. Customertraffic is encapsulated to facilitate routing in the virtual network.

Accordingly, physical addresses (e.g., physical IP addresses) areassociated with components in physical networks and overlay addresses(e.g., overlay IP addresses) are associated with entities in virtual oroverlay networks. A physical IP address is an IP address associated witha physical device (e.g., a network device) in the substrate or physicalnetwork. For example, each NVD has an associated physical IP address. Anoverlay IP address is an overlay address associated with an entity in anoverlay network, such as with a compute instance in a customer's virtualcloud network (VCN). Two different customers or tenants, each with theirown private VCNs can potentially use the same overlay IP address intheir VCNs without any knowledge of each other. Both the physical IPaddresses and overlay IP addresses are types of real IP addresses. Theseare separate from virtual IP addresses. A virtual IP address istypically a single IP address that is represents or maps to multiplereal IP addresses. A virtual IP address provides a 1-to-many mappingbetween the virtual IP address and multiple real IP addresses. Forexample, a load balancer may use a VIP to map to or represent multipleservers, each server having its own real IP address.

The cloud infrastructure or CSPI is physically hosted in one or moredata centers in one or more regions around the world. The CSPI mayinclude components in the physical or substrate network and virtualizedcomponents (e.g., virtual networks, compute instances, virtual machines,etc.) that are in an virtual network built on top of the physicalnetwork components. In certain embodiments, the CSPI is organized andhosted in realms, regions and availability domains. A region istypically a localized geographic area that contains one or more datacenters. Regions are generally independent of each other and can beseparated by vast distances, for example, across countries or evencontinents. For example, a first region may be in Australia, another onein Japan, yet another one in India, and the like. CSPI resources aredivided among regions such that each region has its own independentsubset of CSPI resources. Each region may provide a set of coreinfrastructure services and resources, such as, compute resources (e.g.,bare metal servers, virtual machine, containers and relatedinfrastructure, etc.); storage resources (e.g., block volume storage,file storage, object storage, archive storage); networking resources(e.g., virtual cloud networks (VCNs), load balancing resources,connections to on-premise networks), database resources; edge networkingresources (e.g., DNS); and access management and monitoring resources,and others. Each region generally has multiple paths connecting it toother regions in the realm.

Generally, an application is deployed in a region (i.e., deployed oninfrastructure associated with that region) where it is most heavilyused, because using nearby resources is faster than using distantresources. Applications can also be deployed in different regions forvarious reasons, such as redundancy to mitigate the risk of region-wideevents such as large weather systems or earthquakes, to meet varyingrequirements for legal jurisdictions, tax domains, and other business orsocial criteria, and the like.

The data centers within a region can be further organized and subdividedinto availability domains (ADs). An availability domain may correspondto one or more data centers located within a region. A region can becomposed of one or more availability domains. In such a distributedenvironment, CSPI resources are either region-specific, such as avirtual cloud network (VCN), or availability domain-specific, such as acompute instance.

ADs within a region are isolated from each other, fault tolerant, andare configured such that they are very unlikely to fail simultaneously.This is achieved by the ADs not sharing critical infrastructureresources such as networking, physical cables, cable paths, cable entrypoints, etc., such that a failure at one AD within a region is unlikelyto impact the availability of the other ADs within the same region. TheADs within the same region may be connected to each other by a lowlatency, high bandwidth network, which makes it possible to providehigh-availability connectivity to other networks (e.g., the Internet,customers' on-premise networks, etc.) and to build replicated systems inmultiple ADs for both high-availability and disaster recovery. Cloudservices use multiple ADs to ensure high availability and to protectagainst resource failure. As the infrastructure provided by the IaaSprovider grows, more regions and ADs may be added with additionalcapacity. Traffic between availability domains is usually encrypted.

In certain embodiments, regions are grouped into realms. A realm is alogical collection of regions. Realms are isolated from each other anddo not share any data. Regions in the same realm may communicate witheach other, but regions in different realms cannot. A customer's tenancyor account with the CSP exists in a single realm and can be spreadacross one or more regions that belong to that realm. Typically, when acustomer subscribes to an IaaS service, a tenancy or account is createdfor that customer in the customer-specified region (referred to as the“home” region) within a realm. A customer can extend the customer'stenancy across one or more other regions within the realm. A customercannot access regions that are not in the realm where the customer'stenancy exists.

An IaaS provider can provide multiple realms, each realm catered to aparticular set of customers or users. For example, a commercial realmmay be provided for commercial customers. As another example, a realmmay be provided for a specific country for customers within thatcountry. As yet another example, a government realm may be provided fora government, and the like. For example, the government realm may becatered for a specific government and may have a heightened level ofsecurity than a commercial realm. For example, Oracle CloudInfrastructure (OCI) currently offers a realm for commercial regions andtwo realms (e.g., FedRAMP authorized and IL5 authorized) for governmentcloud regions.

In certain embodiments, an AD can be subdivided into one or more faultdomains. A fault domain is a grouping of infrastructure resources withinan AD to provide anti-affinity. Fault domains allow for the distributionof compute instances such that the instances are not on the samephysical hardware within a single AD. This is known as anti-affinity. Afault domain refers to a set of hardware components (computers,switches, and more) that share a single point of failure. A compute poolis logically divided up into fault domains. Due to this, a hardwarefailure or compute hardware maintenance event that affects one faultdomain does not affect instances in other fault domains. Depending onthe embodiment, the number of fault domains for each AD may vary. Forinstance, in certain embodiments each AD contains three fault domains. Afault domain acts as a logical data center within an AD.

When a customer subscribes to an IaaS service, resources from CSPI areprovisioned for the customer and associated with the customer's tenancy.The customer can use these provisioned resources to build privatenetworks and deploy resources on these networks. The customer networksthat are hosted in the cloud by the CSPI are referred to as virtualcloud networks (VCNs). A customer can set up one or more virtual cloudnetworks (VCNs) using CSPI resources allocated for the customer. A VCNis a virtual or software defined private network. The customer resourcesthat are deployed in the customer's VCN can include compute instances(e.g., virtual machines, bare-metal instances) and other resources.These compute instances may represent various customer workloads such asapplications, load balancers, databases, and the like. A computeinstance deployed on a VCN can communicate with public accessibleendpoints (“public endpoints”) over a public network such as theInternet, with other instances in the same VCN or other VCNs (e.g., thecustomer's other VCNs, or VCNs not belonging to the customer), with thecustomer's on-premise data centers or networks, and with serviceendpoints, and other types of endpoints.

The CSP may provide various services using the CSPI. In some instances,customers of CSPI may themselves act like service providers and provideservices using CSPI resources. A service provider may expose a serviceendpoint, which is characterized by identification information (e.g., anIP Address, a DNS name and port). A customer's resource (e.g., a computeinstance) can consume a particular service by accessing a serviceendpoint exposed by the service for that particular service. Theseservice endpoints are generally endpoints that are publicly accessibleby users using public IP addresses associated with the endpoints via apublic communication network such as the Internet. Network endpointsthat are publicly accessible are also sometimes referred to as publicendpoints.

In certain embodiments, a service provider may expose a service via anendpoint (sometimes referred to as a service endpoint) for the service.Customers of the service can then use this service endpoint to accessthe service. In certain implementations, a service endpoint provided fora service can be accessed by multiple customers that intend to consumethat service. In other implementations, a dedicated service endpoint maybe provided for a customer such that only that customer can access theservice using that dedicated service endpoint.

In certain embodiments, when a VCN is created, it is associated with aprivate overlay Classless Inter-Domain Routing (CIDR) address space,which is a range of private overlay IP addresses that are assigned tothe VCN (e.g., 10.0/16). A VCN includes associated subnets, routetables, and gateways. A VCN resides within a single region but can spanone or more or all of the region's availability domains. A gateway is avirtual interface that is configured for a VCN and enables communicationof traffic to and from the VCN to one or more endpoints outside the VCN.One or more different types of gateways may be configured for a VCN toenable communication to and from different types of endpoints.

A VCN can be subdivided into one or more sub-networks such as one ormore subnets. A subnet is thus a unit of configuration or a subdivisionthat can be created within a VCN. A VCN can have one or multiplesubnets. Each subnet within a VCN is associated with a contiguous rangeof overlay IP addresses (e.g., 10.0.0.0/24 and 10.0.1.0/24) that do notoverlap with other subnets in that VCN and which represent an addressspace subset within the address space of the VCN.

Each compute instance is associated with a virtual network interfacecard (VNIC), that enables the compute instance to participate in asubnet of a VCN. A VNIC is a logical representation of physical NetworkInterface Card (NIC). In general. a VNIC is an interface between anentity (e.g., a compute instance, a service) and a virtual network. AVNIC exists in a subnet, has one or more associated IP addresses, andassociated security rules or policies. A VNIC is equivalent to a Layer-2port on a switch. A VNIC is attached to a compute instance and to asubnet within a VCN. A VNIC associated with a compute instance enablesthe compute instance to be a part of a subnet of a VCN and enables thecompute instance to communicate (e.g., send and receive packets) withendpoints that are on the same subnet as the compute instance, withendpoints in different subnets in the VCN, or with endpoints outside theVCN. The VNIC associated with a compute instance thus determines how thecompute instance connects with endpoints inside and outside the VCN. AVNIC for a compute instance is created and associated with that computeinstance when the compute instance is created and added to a subnetwithin a VCN. For a subnet comprising a set of compute instances, thesubnet contains the VNICs corresponding to the set of compute instances,each VNIC attached to a compute instance within the set of computerinstances.

Each compute instance is assigned a private overlay IP address via theVNIC associated with the compute instance. This private overlay IPaddress is assigned to the VNIC that is associated with the computeinstance when the compute instance is created and used for routingtraffic to and from the compute instance. All VNICs in a given subnetuse the same route table, security lists, and DHCP options. As describedabove, each subnet within a VCN is associated with a contiguous range ofoverlay IP addresses (e.g., 10.0.0.0/24 and 10.0.1.0/24) that do notoverlap with other subnets in that VCN and which represent an addressspace subset within the address space of the VCN. For a VNIC on aparticular subnet of a VCN, the private overlay IP address that isassigned to the VNIC is an address from the contiguous range of overlayIP addresses allocated for the subnet.

In certain embodiments, a compute instance may optionally be assignedadditional overlay IP addresses in addition to the private overlay IPaddress, such as, for example, one or more public IP addresses if in apublic subnet. These multiple addresses are assigned either on the sameVNIC or over multiple VNICs that are associated with the computeinstance. Each instance however has a primary VNIC that is createdduring instance launch and is associated with the overlay private IPaddress assigned to the instance—this primary VNIC cannot be removed.Additional VNICs, referred to as secondary VNICs, can be added to anexisting instance in the same availability domain as the primary VNIC.All the VNICs are in the same availability domain as the instance. Asecondary VNIC can be in a subnet in the same VCN as the primary VNIC,or in a different subnet that is either in the same VCN or a differentone.

A compute instance may optionally be assigned a public IP address if itis in a public subnet. A subnet can be designated as either a publicsubnet or a private subnet at the time the subnet is created. A privatesubnet means that the resources (e.g., compute instances) and associatedVNICs in the subnet cannot have public overlay IP addresses. A publicsubnet means that the resources and associated VNICs in the subnet canhave public IP addresses. A customer can designate a subnet to existeither in a single availability domain or across multiple availabilitydomains in a region or realm.

As described above, a VCN may be subdivided into one or more subnets. Incertain embodiments, a Virtual Router (VR) configured for the VCN(referred to as the VCN VR or just VR) enables communications betweenthe subnets of the VCN. For a subnet within a VCN, the VR represents alogical gateway for that subnet that enables the subnet (i.e., thecompute instances on that subnet) to communicate with endpoints on othersubnets within the VCN, and with other endpoints outside the VCN. TheVCN VR is a logical entity that is configured to route traffic betweenVNICs in the VCN and virtual gateways (“gateways”) associated with theVCN. Gateways are further described below with respect to FIG. 6 . A VCNVR is a Layer-3/IP Layer concept. In one embodiment, there is one VCN VRfor a VCN where the VCN VR has potentially an unlimited number of portsaddressed by IP addresses, with one port for each subnet of the VCN. Inthis manner, the VCN VR has a different IP address for each subnet inthe VCN that the VCN VR is attached to. The VR is also connected to thevarious gateways configured for a VCN. In certain embodiments, aparticular overlay IP address from the overlay IP address range for asubnet is reserved for a port of the VCN VR for that subnet. Forexample, consider a VCN having two subnets with associated addressranges 10.0/16 and 10.1/16, respectively. For the first subnet withinthe VCN with address range 10.0/16, an address from this range isreserved for a port of the VCN VR for that subnet. In some instances,the first IP address from the range may be reserved for the VCN VR. Forexample, for the subnet with overlay IP address range 10.0/16, IPaddress 10.0.0.1 may be reserved for a port of the VCN VR for thatsubnet. For the second subnet within the same VCN with address range10.1/16, the VCN VR may have a port for that second subnet with IPaddress 10.1.0.1. The VCN VR has a different IP address for each of thesubnets in the VCN.

In some other embodiments, each subnet within a VCN may have its ownassociated VR that is addressable by the subnet using a reserved ordefault IP address associated with the VR. The reserved or default IPaddress may, for example, be the first IP address from the range of IPaddresses associated with that subnet. The VNICs in the subnet cancommunicate (e.g., send and receive packets) with the VR associated withthe subnet using this default or reserved IP address. In such anembodiment, the VR is the ingress/egress point for that subnet. The VRassociated with a subnet within the VCN can communicate with other VRsassociated with other subnets within the VCN. The VRs can alsocommunicate with gateways associated with the VCN. The VR function for asubnet is running on or executed by one or more NVDs executing VNICsfunctionality for VNICs in the subnet.

Route tables, security rules, and DHCP options may be configured for aVCN. Route tables are virtual route tables for the VCN and include rulesto route traffic from subnets within the VCN to destinations outside theVCN by way of gateways or specially configured instances. A VCN's routetables can be customized to control how packets are forwarded/routed toand from the VCN. DHCP options refers to configuration information thatis automatically provided to the instances when they boot up.

Security rules configured for a VCN represent overlay firewall rules forthe VCN. The security rules can include ingress and egress rules, andspecify the types of traffic (e.g., based upon protocol and port) thatis allowed in and out of the instances within the VCN. The customer canchoose whether a given rule is stateful or stateless. For instance, thecustomer can allow incoming SSH traffic from anywhere to a set ofinstances by setting up a stateful ingress rule with source CIDR0.0.0.0/0, and destination TCP port 22. Security rules can beimplemented using network security groups or security lists. A networksecurity group consists of a set of security rules that apply only tothe resources in that group. A security list, on the other hand,includes rules that apply to all the resources in any subnet that usesthe security list. A VCN may be provided with a default security listwith default security rules. DHCP options configured for a VCN provideconfiguration information that is automatically provided to theinstances in the VCN when the instances boot up.

In certain embodiments, the configuration information for a VCN isdetermined and stored by a VCN Control Plane. The configurationinformation for a VCN may include, for example, information about: theaddress range associated with the VCN, subnets within the VCN andassociated information, one or more VRs associated with the VCN, computeinstances in the VCN and associated VNICs, NVDs executing the variousvirtualization network functions (e.g., VNICs, VRs, gateways) associatedwith the VCN, state information for the VCN, and other VCN-relatedinformation. In certain embodiments, a VCN Distribution Servicepublishes the configuration information stored by the VCN Control Plane,or portions thereof, to the NVDs. The distributed information may beused to update information (e.g., forwarding tables, routing tables,etc.) stored and used by the NVDs to forward packets to and from thecompute instances in the VCN.

In certain embodiments, the creation of VCNs and subnets are handled bya VCN Control Plane (CP) and the launching of compute instances ishandled by a Compute Control Plane. The Compute Control Plane isresponsible for allocating the physical resources for the computeinstance and then calls the VCN Control Plane to create and attach VNICsto the compute instance. The VCN CP also sends VCN data mappings to theVCN data plane that is configured to perform packet forwarding androuting functions. In certain embodiments, the VCN CP provides adistribution service that is responsible for providing updates to theVCN data plane. Examples of a VCN Control Plane are also depicted inFIGS. 11, 12, 13, and 14 (see references 1116, 1216, 1316, and 1416) anddescribed below.

A customer may create one or more VCNs using resources hosted by CSPI. Acompute instance deployed on a customer VCN may communicate withdifferent endpoints. These endpoints can include endpoints that arehosted by CSPI and endpoints outside CSPI.

Various different architectures for implementing cloud-based serviceusing CSPI are depicted in FIGS. 6, 7, 8, 9, 10, 11, 12, 13, and 15 ,and are described below. FIG. 6 is a high level diagram of a distributedenvironment 600 showing an overlay or customer VCN hosted by CSPIaccording to certain embodiments. The distributed environment depictedin FIG. 6 includes multiple components in the overlay network.Distributed environment 600 depicted in FIG. 6 is merely an example andis not intended to unduly limit the scope of claimed embodiments. Manyvariations, alternatives, and modifications are possible. For example,in some implementations, the distributed environment depicted in FIG. 6may have more or fewer systems or components than those shown in FIG. 1, may combine two or more systems, or may have a different configurationor arrangement of systems.

As shown in the example depicted in FIG. 6 , distributed environment 600comprises CSPI 601 that provides services and resources that customerscan subscribe to and use to build their virtual cloud networks (VCNs).In certain embodiments, CSPI 601 offers IaaS services to subscribingcustomers. The data centers within CSPI 601 may be organized into one ormore regions. One example region “Region US” 602 is shown in FIG. 6 . Acustomer has configured a customer VCN 604 for region 602. The customermay deploy various compute instances on VCN 604, where the computeinstances may include virtual machines or bare metal instances. Examplesof instances include applications, database, load balancers, and thelike.

In the embodiment depicted in FIG. 6 , customer VCN 604 comprises twosubnets, namely, “Subnet-1” and “Subnet-2”, each subnet with its ownCIDR IP address range. In FIG. 6 , the overlay IP address range forSubnet-1 is 10.0/16 and the address range for Subnet-2 is 10.1/16. A VCNVirtual Router 605 represents a logical gateway for the VCN that enablescommunications between subnets of the VCN 604, and with other endpointsoutside the VCN. VCN VR 605 is configured to route traffic between VNICsin VCN 604 and gateways associated with VCN 604. VCN VR 605 provides aport for each subnet of VCN 604. For example, VR 605 may provide a portwith IP address 10.0.0.1 for Subnet-1 and a port with IP address10.1.0.1 for Subnet-2.

Multiple compute instances may be deployed on each subnet, where thecompute instances can be virtual machine instances, and/or bare metalinstances. The compute instances in a subnet may be hosted by one ormore host machines within CSPI 601. A compute instance participates in asubnet via a VNIC associated with the compute instance. For example, asshown in FIG. 6 , a compute instance C1 is part of Subnet-1 via a VNICassociated with the compute instance. Likewise, compute instance C2 ispart of Subnet-1 via a VNIC associated with C2. In a similar manner,multiple compute instances, which may be virtual machine instances orbare metal instances, may be part of Subnet-1. Via its associated VNIC,each compute instance is assigned a private overlay IP address and a MACaddress. For example, in FIG. 6 , compute instance C1 has an overlay IPaddress of 10.0.0.2 and a MAC address of M1, while compute instance C2has an private overlay IP address of 10.0.0.3 and a MAC address of M2.Each compute instance in Subnet-1, including compute instances C1 andC2, has a default route to VCN VR 605 using IP address 10.0.0.1, whichis the IP address for a port of VCN VR 605 for Subnet-1.

Subnet-2 can have multiple compute instances deployed on it, includingvirtual machine instances and/or bare metal instances. For example, asshown in FIG. 6 , compute instances D1 and D2 are part of Subnet-2 viaVNICs associated with the respective compute instances. In theembodiment depicted in FIG. 6 , compute instance D1 has an overlay IPaddress of 10.1.0.2 and a MAC address of MM1, while compute instance D2has an private overlay IP address of 10.1.0.3 and a MAC address of MM2.Each compute instance in Subnet-2, including compute instances D1 andD2, has a default route to VCN VR 605 using IP address 10.1.0.1, whichis the IP address for a port of VCN VR 605 for Subnet-2.

VCN A 604 may also include one or more load balancers. For example, aload balancer may be provided for a subnet and may be configured to loadbalance traffic across multiple compute instances on the subnet. A loadbalancer may also be provided to load balance traffic across subnets inthe VCN.

A particular compute instance deployed on VCN 604 can communicate withvarious different endpoints. These endpoints may include endpoints thatare hosted by CSPI 700 and endpoints outside CSPI 700. Endpoints thatare hosted by CSPI 601 may include: an endpoint on the same subnet asthe particular compute instance (e.g., communications between twocompute instances in Subnet-1); an endpoint on a different subnet butwithin the same VCN (e.g., communication between a compute instance inSubnet-1 and a compute instance in Subnet-2); an endpoint in a differentVCN in the same region (e.g., communications between a compute instancein Subnet-1 and an endpoint in a VCN in the same region 606 or 610,communications between a compute instance in Subnet-1 and an endpoint inservice network 610 in the same region); or an endpoint in a VCN in adifferent region (e.g., communications between a compute instance inSubnet-1 and an endpoint in a VCN in a different region 608). A computeinstance in a subnet hosted by CSPI 601 may also communicate withendpoints that are not hosted by CSPI 601 (i.e., are outside CSPI 601).These outside endpoints include endpoints in the customer's on-premisenetwork 616, endpoints within other remote cloud hosted networks 618,public endpoints 614 accessible via a public network such as theInternet, and other endpoints.

Communications between compute instances on the same subnet arefacilitated using VNICs associated with the source compute instance andthe destination compute instance. For example, compute instance C1 inSubnet-1 may want to send packets to compute instance C2 in Subnet-1.For a packet originating at a source compute instance and whosedestination is another compute instance in the same subnet, the packetis first processed by the VNIC associated with the source computeinstance. Processing performed by the VNIC associated with the sourcecompute instance can include determining destination information for thepacket from the packet headers, identifying any policies (e.g., securitylists) configured for the VNIC associated with the source computeinstance, determining a next hop for the packet, performing any packetencapsulation/decapsulation functions as needed, and thenforwarding/routing the packet to the next hop with the goal offacilitating communication of the packet to its intended destination.When the destination compute instance is in the same subnet as thesource compute instance, the VNIC associated with the source computeinstance is configured to identify the VNIC associated with thedestination compute instance and forward the packet to that VNIC forprocessing. The VNIC associated with the destination compute instance isthen executed and forwards the packet to the destination computeinstance.

For a packet to be communicated from a compute instance in a subnet toan endpoint in a different subnet in the same VCN, the communication isfacilitated by the VNICs associated with the source and destinationcompute instances and the VCN VR. For example, if compute instance C1 inSubnet-1 in FIG. 6 wants to send a packet to compute instance D1 inSubnet-2, the packet is first processed by the VNIC associated withcompute instance C1. The VNIC associated with compute instance C1 isconfigured to route the packet to the VCN VR 605 using default route orport 10.0.0.1 of the VCN VR. VCN VR 605 is configured to route thepacket to Subnet-2 using port 10.1.0.1. The packet is then received andprocessed by the VNIC associated with D1 and the VNIC forwards thepacket to compute instance D1.

For a packet to be communicated from a compute instance in VCN 604 to anendpoint that is outside VCN 604, the communication is facilitated bythe VNIC associated with the source compute instance, VCN VR 605, andgateways associated with VCN 604. One or more types of gateways may beassociated with VCN 604. A gateway is an interface between a VCN andanother endpoint, where the another endpoint is outside the VCN. Agateway is a Layer-3/IP layer concept and enables a VCN to communicatewith endpoints outside the VCN. A gateway thus facilitates traffic flowbetween a VCN and other VCNs or networks. Various different types ofgateways may be configured for a VCN to facilitate different types ofcommunications with different types of endpoints. Depending upon thegateway, the communications may be over public networks (e.g., theInternet) or over private networks. Various communication protocols maybe used for these communications.

For example, compute instance C1 may want to communicate with anendpoint outside VCN 604. The packet may be first processed by the VNICassociated with source compute instance C1. The VNIC processingdetermines that the destination for the packet is outside the Subnet-1of C1. The VNIC associated with C1 may forward the packet to VCN VR 605for VCN 604. VCN VR 605 then processes the packet and as part of theprocessing, based upon the destination for the packet, determines aparticular gateway associated with VCN 604 as the next hop for thepacket. VCN VR 605 may then forward the packet to the particularidentified gateway. For example, if the destination is an endpointwithin the customer's on-premise network, then the packet may beforwarded by VCN VR 605 to Dynamic Routing Gateway (DRG) gateway 622configured for VCN 604. The packet may then be forwarded from thegateway to a next hop to facilitate communication of the packet to itfinal intended destination.

Various different types of gateways may be configured for a VCN.Examples of gateways that may be configured for a VCN are depicted inFIG. 6 and described below. Examples of gateways associated with a VCNare also depicted in FIGS. 11, 12, 13, and 14 (for example, gatewaysreferenced by reference numbers 1134, 1136, 1138, 1234, 1236, 1238,1334, 1336, 1338, 1434, 1436, and 1438) and described below. As shown inthe embodiment depicted in FIG. 6 , a Dynamic Routing Gateway (DRG) 622may be added to or be associated with customer VCN 604 and provides apath for private network traffic communication between customer VCN 604and another endpoint, where the another endpoint can be the customer'son-premise network 616, a VCN 608 in a different region of CSPI 601, orother remote cloud networks 618 not hosted by CSPI 601. Customeron-premise network 616 may be a customer network or a customer datacenter built using the customer's resources. Access to customeron-premise network 616 is generally very restricted. For a customer thathas both a customer on-premise network 616 and one or more VCNs 604deployed or hosted in the cloud by CSPI 601, the customer may want theiron-premise network 616 and their cloud-based VCN 604 to be able tocommunicate with each other. This enables a customer to build anextended hybrid environment encompassing the customer's VCN 604 hostedby CSPI 601 and their on-premises network 616. DRG 622 enables thiscommunication. To enable such communications, a communication channel624 is set up where one endpoint of the channel is in customeron-premise network 616 and the other endpoint is in CSPI 601 andconnected to customer VCN 604. Communication channel 624 can be overpublic communication networks such as the Internet or privatecommunication networks. Various different communication protocols may beused such as IPsec VPN technology over a public communication networksuch as the Internet, Oracle's FastConnect technology that uses aprivate network instead of a public network, and others. The device orequipment in customer on-premise network 616 that forms one end pointfor communication channel 624 is referred to as the customer premiseequipment (CPE), such as CPE 626 depicted in FIG. 6 . On the CSPI 601side, the endpoint may be a host machine executing DRG 622.

In certain embodiments, a Remote Peering Connection (RPC) can be addedto a DRG, which allows a customer to peer one VCN with another VCN in adifferent region. Using such an RPC, customer VCN 604 can use DRG 622 toconnect with a VCN 608 in another region. DRG 622 may also be used tocommunicate with other remote cloud networks 618, not hosted by CSPI 601such as a Microsoft Azure cloud, Amazon AWS cloud, and others.

As shown in FIG. 6 , an Internet Gateway (IGW) 620 may be configured forcustomer VCN 604 the enables a compute instance on VCN 604 tocommunicate with public endpoints 614 accessible over a public networksuch as the Internet. IGW 620 is a gateway that connects a VCN to apublic network such as the Internet. IGW 620 enables a public subnet(where the resources in the public subnet have public overlay IPaddresses) within a VCN, such as VCN 604, direct access to publicendpoints 612 on a public network 614 such as the Internet. Using IGW620, connections can be initiated from a subnet within VCN 604 or fromthe Internet.

A Network Address Translation (NAT) gateway 628 can be configured forcustomer's VCN 604 and enables cloud resources in the customer's VCN,which do not have dedicated public overlay IP addresses, access to theInternet and it does so without exposing those resources to directincoming Internet connections (e.g., L4-L7 connections). This enables aprivate subnet within a VCN, such as private Subnet-1 in VCN 604, withprivate access to public endpoints on the Internet. In NAT gateways,connections can be initiated only from the private subnet to the publicInternet and not from the Internet to the private subnet.

In certain embodiments, a Service Gateway (SGW) 626 can be configuredfor customer VCN 604 and provides a path for private network trafficbetween VCN 604 and supported services endpoints in a service network610. In certain embodiments, service network 610 may be provided by theCSP and may provide various services. An example of such a servicenetwork is Oracle's Services Network, which provides various servicesthat can be used by customers. For example, a compute instance (e.g., adatabase system) in a private subnet of customer VCN 604 can back updata to a service endpoint (e.g., Object Storage) without needing publicIP addresses or access to the Internet. In certain embodiments, a VCNcan have only one SGW, and connections can only be initiated from asubnet within the VCN and not from service network 610. If a VCN ispeered with another, resources in the other VCN typically cannot accessthe SGW. Resources in on-premises networks that are connected to a VCNwith FastConnect or VPN Connect can also use the service gatewayconfigured for that VCN.

In certain implementations, SGW 626 uses the concept of a serviceClassless Inter-Domain Routing (CIDR) label, which is a string thatrepresents all the regional public IP address ranges for the service orgroup of services of interest. The customer uses the service CIDR labelwhen they configure the SGW and related route rules to control trafficto the service. The customer can optionally utilize it when configuringsecurity rules without needing to adjust them if the service's public IPaddresses change in the future.

A Local Peering Gateway (LPG) 632 is a gateway that can be added tocustomer VCN 604 and enables VCN 604 to peer with another VCN in thesame region. Peering means that the VCNs communicate using private IPaddresses, without the traffic traversing a public network such as theInternet or without routing the traffic through the customer'son-premises network 616. In preferred embodiments, a VCN has a separateLPG for each peering it establishes. Local Peering or VCN Peering is acommon practice used to establish network connectivity between differentapplications or infrastructure management functions.

Service providers, such as providers of services in service network 610,may provide access to services using different access models. Accordingto a public access model, services may be exposed as public endpointsthat are publicly accessible by compute instance in a customer VCN via apublic network such as the Internet and or may be privately accessiblevia SGW 626. According to a specific private access model, services aremade accessible as private IP endpoints in a private subnet in thecustomer's VCN. This is referred to as a Private Endpoint (PE) accessand enables a service provider to expose their service as an instance inthe customer's private network. A Private Endpoint resource represents aservice within the customer's VCN. Each PE manifests as a VNIC (referredto as a PE-VNIC, with one or more private IPs) in a subnet chosen by thecustomer in the customer's VCN. APE thus provides a way to present aservice within a private customer VCN subnet using a VNIC. Since theendpoint is exposed as a VNIC, all the features associates with a VNICsuch as routing rules, security lists, etc., are now available for thePE VNIC.

A service provider can register their service to enable access through aPE. The provider can associate policies with the service that restrictsthe service's visibility to the customer tenancies. A provider canregister multiple services under a single virtual IP address (VIP),especially for multi-tenant services. There may be multiple such privateendpoints (in multiple VCNs) that represent the same service.

Compute instances in the private subnet can then use the PE VNIC'sprivate IP address or the service DNS name to access the service.Compute instances in the customer VCN can access the service by sendingtraffic to the private IP address of the PE in the customer VCN. APrivate Access Gateway (PAGW) 630 is a gateway resource that can beattached to a service provider VCN (e.g., a VCN in service network 610)that acts as an ingress/egress point for all traffic from/to customersubnet private endpoints. PAGW 630 enables a provider to scale thenumber of PE connections without utilizing its internal IP addressresources. A provider needs only configure one PAGW for any number ofservices registered in a single VCN. Providers can represent a serviceas a private endpoint in multiple VCNs of one or more customers. Fromthe customer's perspective, the PE VNIC, which, instead of beingattached to a customer's instance, appears attached to the service withwhich the customer wishes to interact. The traffic destined to theprivate endpoint is routed via PAGW 630 to the service. These arereferred to as customer-to-service private connections (C2Sconnections).

The PE concept can also be used to extend the private access for theservice to customer's on-premises networks and data centers, by allowingthe traffic to flow through FastConnect/IPsec links and the privateendpoint in the customer VCN. Private access for the service can also beextended to the customer's peered VCNs, by allowing the traffic to flowbetween LPG 632 and the PE in the customer's VCN.

A customer can control routing in a VCN at the subnet level, so thecustomer can specify which subnets in the customer's VCN, such as VCN604, use each gateway. A VCN's route tables are used to decide iftraffic is allowed out of a VCN through a particular gateway. Forexample, in a particular instance, a route table for a public subnetwithin customer VCN 604 may send non-local traffic through IGW 620. Theroute table for a private subnet within the same customer VCN 604 maysend traffic destined for CSP services through SGW 626. All remainingtraffic may be sent via the NAT gateway 628. Route tables only controltraffic going out of a VCN.

Security lists associated with a VCN are used to control traffic thatcomes into a VCN via a gateway via inbound connections. All resources ina subnet use the same route table and security lists. Security lists maybe used to control specific types of traffic allowed in and out ofinstances in a subnet of a VCN. Security list rules may comprise ingress(inbound) and egress (outbound) rules. For example, an ingress rule mayspecify an allowed source address range, while an egress rule mayspecify an allowed destination address range. Security rules may specifya particular protocol (e.g., TCP, ICMP), a particular port (e.g., 22 forSSH, 3389 for Windows RDP), etc. In certain implementations, aninstance's operating system may enforce its own firewall rules that arealigned with the security list rules. Rules may be stateful (e.g., aconnection is tracked and the response is automatically allowed withoutan explicit security list rule for the response traffic) or stateless.

Access from a customer VCN (i.e., by a resource or compute instancedeployed on VCN 604) can be categorized as public access, privateaccess, or dedicated access. Public access refers to an access modelwhere a public IP address or a NAT is used to access a public endpoint.Private access enables customer workloads in VCN 604 with private IPaddresses (e.g., resources in a private subnet) to access serviceswithout traversing a public network such as the Internet. In certainembodiments, CSPI 601 enables customer VCN workloads with private IPaddresses to access the (public service endpoints of) services using aservice gateway. A service gateway thus offers a private access model byestablishing a virtual link between the customer's VCN and the service'spublic endpoint residing outside the customer's private network.

Additionally, CSPI may offer dedicated public access using technologiessuch as FastConnect public peering where customer on-premises instancescan access one or more services in a customer VCN using a FastConnectconnection and without traversing a public network such as the Internet.CSPI also may also offer dedicated private access using FastConnectprivate peering where customer on-premises instances with private IPaddresses can access the customer's VCN workloads using a FastConnectconnection. FastConnect is a network connectivity alternative to usingthe public Internet to connect a customer's on-premise network to CSPIand its services. FastConnect provides an easy, elastic, and economicalway to create a dedicated and private connection with higher bandwidthoptions and a more reliable and consistent networking experience whencompared to Internet-based connections.

FIG. 6 and the accompanying description above describes variousvirtualized components in an example virtual network. As describedabove, the virtual network is built on the underlying physical orsubstrate network. FIG. 7 depicts a simplified architectural diagram ofthe physical components in the physical network within CSPI 700 thatprovide the underlay for the virtual network according to certainembodiments. As shown, CSPI 700 provides a distributed environmentcomprising components and resources (e.g., compute, memory, andnetworking resources) provided by a cloud service provider (CSP). Thesecomponents and resources are used to provide cloud services (e.g., IaaSservices) to subscribing customers, i.e., customers that have subscribedto one or more services provided by the CSP. Based upon the servicessubscribed to by a customer, a subset of resources (e.g., compute,memory, and networking resources) of CSPI 700 are provisioned for thecustomer. Customers can then build their own cloud-based (i.e.,CSPI-hosted) customizable and private virtual networks using physicalcompute, memory, and networking resources provided by CSPI 700. Aspreviously indicated, these customer networks are referred to as virtualcloud networks (VCNs). A customer can deploy one or more customerresources, such as compute instances, on these customer VCNs. Computeinstances can be in the form of virtual machines, bare metal instances,and the like. CSPI 700 provides infrastructure and a set ofcomplementary cloud services that enable customers to build and run awide range of applications and services in a highly available hostedenvironment.

In the example embodiment depicted in FIG. 7 , the physical componentsof CSPI 700 include one or more physical host machines or physicalservers (e.g., 702, 706, 708), network virtualization devices (NVDs)(e.g., 710, 712), top-of-rack (TOR) switches (e.g., 714, 716), and aphysical network (e.g., 718), and switches in physical network 718. Thephysical host machines or servers may host and execute various computeinstances that participate in one or more subnets of a VCN. The computeinstances may include virtual machine instances, and bare metalinstances. For example, the various compute instances depicted in FIG. 6may be hosted by the physical host machines depicted in FIG. 7 . Thevirtual machine compute instances in a VCN may be executed by one hostmachine or by multiple different host machines. The physical hostmachines may also host virtual host machines, container-based hosts orfunctions, and the like. The VNICs and VCN VR depicted in FIG. 6 may beexecuted by the NVDs depicted in FIG. 7 . The gateways depicted in FIG.6 may be executed by the host machines and/or by the NVDs depicted inFIG. 7 .

The host machines or servers may execute a hypervisor (also referred toas a virtual machine monitor or VMM) that creates and enables avirtualized environment on the host machines. The virtualization orvirtualized environment facilitates cloud-based computing. One or morecompute instances may be created, executed, and managed on a hostmachine by a hypervisor on that host machine. The hypervisor on a hostmachine enables the physical computing resources of the host machine(e.g., compute, memory, and networking resources) to be shared betweenthe various compute instances executed by the host machine.

For example, as depicted in FIG. 7 , host machines 702 and 708 executehypervisors 760 and 766, respectively. These hypervisors may beimplemented using software, firmware, or hardware, or combinationsthereof. Typically, a hypervisor is a process or a software layer thatsits on top of the host machine's operating system (OS), which in turnexecutes on the hardware processors of the host machine. The hypervisorprovides a virtualized environment by enabling the physical computingresources (e.g., processing resources such as processors/cores, memoryresources, networking resources) of the host machine to be shared amongthe various virtual machine compute instances executed by the hostmachine. For example, in FIG. 7 , hypervisor 760 may sit on top of theOS of host machine 702 and enables the computing resources (e.g.,processing, memory, and networking resources) of host machine 702 to beshared between compute instances (e.g., virtual machines) executed byhost machine 702. A virtual machine can have its own operating system(referred to as a guest operating system), which may be the same as ordifferent from the OS of the host machine. The operating system of avirtual machine executed by a host machine may be the same as ordifferent from the operating system of another virtual machine executedby the same host machine. A hypervisor thus enables multiple operatingsystems to be executed alongside each other while sharing the samecomputing resources of the host machine. The host machines depicted inFIG. 7 may have the same or different types of hypervisors.

A compute instance can be a virtual machine instance or a bare metalinstance. In FIG. 7 , compute instances 768 on host machine 702 and 774on host machine 708 are examples of virtual machine instances. Hostmachine 706 is an example of a bare metal instance that is provided to acustomer.

In certain instances, an entire host machine may be provisioned to asingle customer, and all of the one or more compute instances (eithervirtual machines or bare metal instance) hosted by that host machinebelong to that same customer. In other instances, a host machine may beshared between multiple customers (i.e., multiple tenants). In such amulti-tenancy scenario, a host machine may host virtual machine computeinstances belonging to different customers. These compute instances maybe members of different VCNs of different customers. In certainembodiments, a bare metal compute instance is hosted by a bare metalserver without a hypervisor. When a bare metal compute instance isprovisioned, a single customer or tenant maintains control of thephysical CPU, memory, and network interfaces of the host machine hostingthe bare metal instance and the host machine is not shared with othercustomers or tenants.

As previously described, each compute instance that is part of a VCN isassociated with a VNIC that enables the compute instance to become amember of a subnet of the VCN. The VNIC associated with a computeinstance facilitates the communication of packets or frames to and fromthe compute instance. A VNIC is associated with a compute instance whenthe compute instance is created. In certain embodiments, for a computeinstance executed by a host machine, the VNIC associated with thatcompute instance is executed by an NVD connected to the host machine.For example, in FIG. 7 , host machine 702 executes a virtual machinecompute instance 768 that is associated with VNIC 776, and VNIC 776 isexecuted by NVD 710 connected to host machine 702. As another example,bare metal instance 772 hosted by host machine 706 is associated withVNIC 780 that is executed by NVD 712 connected to host machine 706. Asyet another example, VNIC 784 is associated with compute instance 774executed by host machine 708, and VNIC 784 is executed by NVD 712connected to host machine 708.

For compute instances hosted by a host machine, an NVD connected to thathost machine also executes VCN VRs corresponding to VCNs of which thecompute instances are members. For example, in the embodiment depictedin FIG. 7 , NVD 710 executes VCN VR 777 corresponding to the VCN ofwhich compute instance 768 is a member. NVD 712 may also execute one ormore VCN VRs 783 corresponding to VCNs corresponding to the computeinstances hosted by host machines 706 and 708.

A host machine may include one or more network interface cards (NIC)that enable the host machine to be connected to other devices. A NIC ona host machine may provide one or more ports (or interfaces) that enablethe host machine to be communicatively connected to another device. Forexample, a host machine may be connected to an NVD using one or moreports (or interfaces) provided on the host machine and on the NVD. Ahost machine may also be connected to other devices such as another hostmachine.

For example, in FIG. 7 , host machine 702 is connected to NVD 710 usinglink 720 that extends between a port 734 provided by a NIC 732 of hostmachine 702 and between a port 736 of NVD 710. Host machine 706 isconnected to NVD 712 using link 724 that extends between a port 746provided by a NIC 744 of host machine 706 and between a port 748 of NVD712. Host machine 708 is connected to NVD 712 using link 726 thatextends between a port 752 provided by a NIC 750 of host machine 708 andbetween a port 754 of NVD 712.

The NVDs are in turn connected via communication links totop-of-the-rack (TOR) switches, which are connected to physical network718 (also referred to as the switch fabric). In certain embodiments, thelinks between a host machine and an NVD, and between an NVD and a TORswitch are Ethernet links. For example, in FIG. 7 , NVDs 710 and 712 areconnected to 1126 TOR switches 714 and 716, respectively, using links728 and 730. In certain embodiments, the links 720, 724, 726, 728, and730 are Ethernet links. The collection of host machines and NVDs thatare connected to a TOR is sometimes referred to as a rack.

Physical network 718 provides a communication fabric that enables TORswitches to communicate with each other. Physical network 718 can be amulti-tiered network. In certain implementations, physical network 718is a multi-tiered Clos network of switches, with TOR switches 714 and716 representing the leaf level nodes of the multi-tiered and multi-nodephysical switching network 718. Different Clos network configurationsare possible including but not limited to a 2-tier network, a 3-tiernetwork, a 4-tier network, a 5-tier network, and in general a “n”-tierednetwork. An example of a Clos network is depicted in FIG. 10 anddescribed below.

Various different connection configurations are possible between hostmachines and NVDs such as one-to-one configuration, many-to-oneconfiguration, one-to-many configuration, and others. In a one-to-oneconfiguration implementation, each host machine is connected to its ownseparate NVD. For example, in FIG. 7 , host machine 702 is connected toNVD 710 via NIC 732 of host machine 702. In a many-to-one configuration,multiple host machines are connected to one NVD. For example, in FIG. 7, host machines 706 and 708 are connected to the same NVD 712 via NICs744 and 750, respectively.

In a one-to-many configuration, one host machine is connected tomultiple NVDs. FIG. 8 shows an example within CSPI 800 where a hostmachine is connected to multiple NVDs. As shown in FIG. 8 , host machine802 comprises a network interface card (NIC) 804 that includes multipleports 806 and 808. Host machine 800 is connected to a first NVD 810 viaport 806 and link 820, and connected to a second NVD 812 via port 808and link 822. Ports 806 and 808 may be Ethernet ports and the links 820and 822 between host machine 802 and NVDs 810 and 812 may be Ethernetlinks. NVD 810 is in turn connected to a first TOR switch 814 and NVD812 is connected to a second TOR switch 816. The links between NVDs 810and 812, and TOR switches 814 and 816 may be Ethernet links. TORswitches 814 and 816 represent the Tier-0 switching devices inmulti-tiered physical network 818.

The arrangement depicted in FIG. 8 provides two separate physicalnetwork paths to and from physical switch network 818 to host machine802: a first path traversing TOR switch 814 to NVD 810 to host machine802, and a second path traversing TOR switch 816 to NVD 812 to hostmachine 802. The separate paths provide for enhanced availability(referred to as high availability) of host machine 802. If there areproblems in one of the paths (e.g., a link in one of the paths goesdown) or devices (e.g., a particular NVD is not functioning), then theother path may be used for communications to/from host machine 802.

In the configuration depicted in FIG. 8 , the host machine is connectedto two different NVDs using two different ports provided by a NIC of thehost machine. In other embodiments, a host machine may include multipleNICs that enable connectivity of the host machine to multiple NVDs.

Referring back to FIG. 7 , an NVD is a physical device or component thatperforms one or more network and/or storage virtualization functions. AnNVD may be any device with one or more processing units (e.g., CPUs,Network Processing Units (NPUs), FPGAs, packet processing pipelines,etc.), memory including cache, and ports. The various virtualizationfunctions may be performed by software/firmware executed by the one ormore processing units of the NVD.

An NVD may be implemented in various different forms. For example, incertain embodiments, an NVD is implemented as an interface card referredto as a smartNIC or an intelligent NIC with an embedded processoronboard. A smartNIC is a separate device from the NICs on the hostmachines. In FIG. 7 , the NVDs 710 and 712 may be implemented assmartNICs that are connected to host machines 702, and host machines 706and 708, respectively.

A smartNIC is however just one example of an NVD implementation. Variousother implementations are possible. For example, in some otherimplementations, an NVD or one or more functions performed by the NVDmay be incorporated into or performed by one or more host machines, oneor more TOR switches, and other components of CSPI 700. For example, anNVD may be embodied in a host machine where the functions performed byan NVD are performed by the host machine. As another example, an NVD maybe part of a TOR switch or a TOR switch may be configured to performfunctions performed by an NVD that enables the TOR switch to performvarious complex packet transformations that are used for a public cloud.A TOR that performs the functions of an NVD is sometimes referred to asa smart TOR. In yet other implementations, where virtual machines (VMs)instances, but not bare metal (BM) instances, are offered to customers,functions performed by an NVD may be implemented inside a hypervisor ofthe host machine. In some other implementations, some of the functionsof the NVD may be offloaded to a centralized service running on a fleetof host machines.

In certain embodiments, such as when implemented as a smartNIC as shownin FIG. 7 , an NVD may comprise multiple physical ports that enable itto be connected to one or more host machines and to one or more TORswitches. A port on an NVD can be classified as a host-facing port (alsoreferred to as a “south port”) or a network-facing or TOR-facing port(also referred to as a “north port”). A host-facing port of an NVD is aport that is used to connect the NVD to a host machine. Examples ofhost-facing ports in FIG. 7 include port 736 on NVD 710, and ports 748and 754 on NVD 712. A network-facing port of an NVD is a port that isused to connect the NVD to a TOR switch. Examples of network-facingports in FIG. 7 include port 756 on NVD 710, and port 758 on NVD 712. Asshown in FIG. 7 , NVD 710 is connected to TOR switch 714 using link 728that extends from port 756 of NVD 710 to the TOR switch 714. Likewise,NVD 712 is connected to TOR switch 716 using link 730 that extends fromport 758 of NVD 712 to the TOR switch 716.

An NVD receives packets and frames from a host machine (e.g., packetsand frames generated by a compute instance hosted by the host machine)via a host-facing port and, after performing the necessary packetprocessing, may forward the packets and frames to a TOR switch via anetwork-facing port of the NVD. An NVD may receive packets and framesfrom a TOR switch via a network-facing port of the NVD and, afterperforming the necessary packet processing, may forward the packets andframes to a host machine via a host-facing port of the NVD.

In certain embodiments, there may be multiple ports and associated linksbetween an NVD and a TOR switch. These ports and links may be aggregatedto form a link aggregator group of multiple ports or links (referred toas a LAG). Link aggregation allows multiple physical links between twoend-points (e.g., between an NVD and a TOR switch) to be treated as asingle logical link. All the physical links in a given LAG may operatein full-duplex mode at the same speed. LAGs help increase the bandwidthand reliability of the connection between two endpoints. If one of thephysical links in the LAG goes down, traffic is dynamically andtransparently reassigned to one of the other physical links in the LAG.The aggregated physical links deliver higher bandwidth than eachindividual link. The multiple ports associated with a LAG are treated asa single logical port. Traffic can be load-balanced across the multiplephysical links of a LAG. One or more LAGs may be configured between twoendpoints. The two endpoints may be between an NVD and a TOR switch,between a host machine and an NVD, and the like.

An NVD implements or performs network virtualization functions. Thesefunctions are performed by software/firmware executed by the NVD.Examples of network virtualization functions include without limitation:packet encapsulation and de-capsulation functions; functions forcreating a VCN network; functions for implementing network policies suchas VCN security list (firewall) functionality; functions that facilitatethe routing and forwarding of packets to and from compute instances in aVCN; and the like. In certain embodiments, upon receiving a packet, anNVD is configured to execute a packet processing pipeline for processingthe packet and determining how the packet is to be forwarded or routed.As part of this packet processing pipeline, the NVD may execute one ormore virtual functions associated with the overlay network such asexecuting VNICs associated with compute instances in the VCN, executinga Virtual Router (VR) associated with the VCN, the encapsulation anddecapsulation of packets to facilitate forwarding or routing in thevirtual network, execution of certain gateways (e.g., the Local PeeringGateway), the implementation of Security Lists, Network Security Groups,network address translation (NAT) functionality (e.g., the translationof Public IP to Private IP on a host by host basis), throttlingfunctions, and other functions.

In certain embodiments, the packet processing data path in an NVD maycomprise multiple packet pipelines, each composed of a series of packettransformation stages. In certain implementations, upon receiving apacket, the packet is parsed and classified to a single pipeline. Thepacket is then processed in a linear fashion, one stage after another,until the packet is either dropped or sent out over an interface of theNVD. These stages provide basic functional packet processing buildingblocks (e.g., validating headers, enforcing throttle, inserting newLayer-2 headers, enforcing L4 firewall, VCN encapsulation/decapsulation,etc.) so that new pipelines can be constructed by composing existingstages, and new functionality can be added by creating new stages andinserting them into existing pipelines.

An NVD may perform both control plane and data plane functionscorresponding to a control plane and a data plane of a VCN. Examples ofa VCN Control Plane are also depicted in FIGS. 11, 12, 13, and 14 (seereferences 1116, 1216, 1316, and 1416) and described below. Examples ofa VCN Data Plane are depicted in FIGS. 11, 12, 13, and 14 (seereferences 1118, 1218, 1318, and 1418) and described below. The controlplane functions include functions used for configuring a network (e.g.,setting up routes and route tables, configuring VNICs, etc.) thatcontrols how data is to be forwarded. In certain embodiments, a VCNControl Plane is provided that computes all the overlay-to-substratemappings centrally and publishes them to the NVDs and to the virtualnetwork edge devices such as various gateways such as the DRG, the SGW,the IGW, etc. Firewall rules may also be published using the samemechanism. In certain embodiments, an NVD only gets the mappings thatare relevant for that NVD. The data plane functions include functionsfor the actual routing/forwarding of a packet based upon configurationset up using control plane. A VCN data plane is implemented byencapsulating the customer's network packets before they traverse thesubstrate network. The encapsulation/decapsulation functionality isimplemented on the NVDs. In certain embodiments, an NVD is configured tointercept all network packets in and out of host machines and performnetwork virtualization functions.

As indicated above, an NVD executes various virtualization functionsincluding VNICs and VCN VRs. An NVD may execute VNICs associated withthe compute instances hosted by one or more host machines connected tothe VNIC. For example, as depicted in FIG. 7 , NVD 710 executes thefunctionality for VNIC 776 that is associated with compute instance 768hosted by host machine 702 connected to NVD 710. As another example, NVD712 executes VNIC 780 that is associated with bare metal computeinstance 772 hosted by host machine 706, and executes VNIC 784 that isassociated with compute instance 774 hosted by host machine 708. A hostmachine may host compute instances belonging to different VCNs, whichbelong to different customers, and the NVD connected to the host machinemay execute the VNICs (i.e., execute VNICs-relate functionality)corresponding to the compute instances.

An NVD also executes VCN Virtual Routers corresponding to the VCNs ofthe compute instances. For example, in the embodiment depicted in FIG. 7, NVD 710 executes VCN VR 777 corresponding to the VCN to which computeinstance 768 belongs. NVD 712 executes one or more VCN VRs 783corresponding to one or more VCNs to which compute instances hosted byhost machines 706 and 708 belong. In certain embodiments, the VCN VRcorresponding to that VCN is executed by all the NVDs connected to hostmachines that host at least one compute instance belonging to that VCN.If a host machine hosts compute instances belonging to different VCNs,an NVD connected to that host machine may execute VCN VRs correspondingto those different VCNs.

In addition to VNICs and VCN VRs, an NVD may execute various software(e.g., daemons) and include one or more hardware components thatfacilitate the various network virtualization functions performed by theNVD. For purposes of simplicity, these various components are groupedtogether as “packet processing components” shown in FIG. 7 . Forexample, NVD 710 comprises packet processing components 786 and NVD 712comprises packet processing components 788. For example, the packetprocessing components for an NVD may include a packet processor that isconfigured to interact with the NVD's ports and hardware interfaces tomonitor all packets received by and communicated using the NVD and storenetwork information. The network information may, for example, includenetwork flow information identifying different network flows handled bythe NVD and per flow information (e.g., per flow statistics). In certainembodiments, network flows information may be stored on a per VNICbasis. The packet processor may perform packet-by-packet manipulationsas well as implement stateful NAT and L4 firewall (FW). As anotherexample, the packet processing components may include a replicationagent that is configured to replicate information stored by the NVD toone or more different replication target stores. As yet another example,the packet processing components may include a logging agent that isconfigured to perform logging functions for the NVD. The packetprocessing components may also include software for monitoring theperformance and health of the NVD and, also possibly of monitoring thestate and health of other components connected to the NVD.

FIG. 6 shows the components of an example virtual or overlay networkincluding a VCN, subnets within the VCN, compute instances deployed onsubnets, VNICs associated with the compute instances, a VR for a VCN,and a set of gateways configured for the VCN. The overlay componentsdepicted in FIG. 6 may be executed or hosted by one or more of thephysical components depicted in FIG. 7 . For example, the computeinstances in a VCN may be executed or hosted by one or more hostmachines depicted in FIG. 7 . For a compute instance hosted by a hostmachine, the VNIC associated with that compute instance is typicallyexecuted by an NVD connected to that host machine (i.e., the VNICfunctionality is provided by the NVD connected to that host machine).The VCN VR function for a VCN is executed by all the NVDs that areconnected to host machines hosting or executing the compute instancesthat are part of that VCN. The gateways associated with a VCN may beexecuted by one or more different types of NVDs. For example, certaingateways may be executed by smartNICs, while others may be executed byone or more host machines or other implementations of NVDs.

As described above, a compute instance in a customer VCN may communicatewith various different endpoints, where the endpoints can be within thesame subnet as the source compute instance, in a different subnet butwithin the same VCN as the source compute instance, or with an endpointthat is outside the VCN of the source compute instance. Thesecommunications are facilitated using VNICs associated with the computeinstances, the VCN VRs, and the gateways associated with the VCNs.

For communications between two compute instances on the same subnet in aVCN, the communication is facilitated using VNICs associated with thesource and destination compute instances. The source and destinationcompute instances may be hosted by the same host machine or by differenthost machines. A packet originating from a source compute instance maybe forwarded from a host machine hosting the source compute instance toan NVD connected to that host machine. On the NVD, the packet isprocessed using a packet processing pipeline, which can includeexecution of the VNIC associated with the source compute instance. Sincethe destination endpoint for the packet is within the same subnet,execution of the VNIC associated with the source compute instanceresults in the packet being forwarded to an NVD executing the VNICassociated with the destination compute instance, which then processesand forwards the packet to the destination compute instance. The VNICsassociated with the source and destination compute instances may beexecuted on the same NVD (e.g., when both the source and destinationcompute instances are hosted by the same host machine) or on differentNVDs (e.g., when the source and destination compute instances are hostedby different host machines connected to different NVDs). The VNICs mayuse routing/forwarding tables stored by the NVD to determine the nexthop for the packet.

For a packet to be communicated from a compute instance in a subnet toan endpoint in a different subnet in the same VCN, the packetoriginating from the source compute instance is communicated from thehost machine hosting the source compute instance to the NVD connected tothat host machine. On the NVD, the packet is processed using a packetprocessing pipeline, which can include execution of one or more VNICs,and the VR associated with the VCN. For example, as part of the packetprocessing pipeline, the NVD executes or invokes functionalitycorresponding to the VNIC (also referred to as executes the VNIC)associated with source compute instance. The functionality performed bythe VNIC may include looking at the VLAN tag on the packet. Since thepacket's destination is outside the subnet, the VCN VR functionality isnext invoked and executed by the NVD. The VCN VR then routes the packetto the NVD executing the VNIC associated with the destination computeinstance. The VNIC associated with the destination compute instance thenprocesses the packet and forwards the packet to the destination computeinstance. The VNICs associated with the source and destination computeinstances may be executed on the same NVD (e.g., when both the sourceand destination compute instances are hosted by the same host machine)or on different NVDs (e.g., when the source and destination computeinstances are hosted by different host machines connected to differentNVDs).

If the destination for the packet is outside the VCN of the sourcecompute instance, then the packet originating from the source computeinstance is communicated from the host machine hosting the sourcecompute instance to the NVD connected to that host machine. The NVDexecutes the VNIC associated with the source compute instance. Since thedestination end point of the packet is outside the VCN, the packet isthen processed by the VCN VR for that VCN. The NVD invokes the VCN VRfunctionality, which may result in the packet being forwarded to an NVDexecuting the appropriate gateway associated with the VCN. For example,if the destination is an endpoint within the customer's on-premisenetwork, then the packet may be forwarded by the VCN VR to the NVDexecuting the DRG gateway configured for the VCN. The VCN VR may beexecuted on the same NVD as the NVD executing the VNIC associated withthe source compute instance or by a different NVD. The gateway may beexecuted by an NVD, which may be a smartNIC, a host machine, or otherNVD implementation. The packet is then processed by the gateway andforwarded to a next hop that facilitates communication of the packet toits intended destination endpoint. For example, in the embodimentdepicted in FIG. 7 , a packet originating from compute instance 768 maybe communicated from host machine 702 to NVD 710 over link 720 (usingNIC 732). On NVD 710, VNIC 776 is invoked since it is the VNICassociated with source compute instance 768. VNIC 776 is configured toexamine the encapsulated information in the packet, and determine a nexthop for forwarding the packet with the goal of facilitatingcommunication of the packet to its intended destination endpoint, andthen forward the packet to the determined next hop.

A compute instance deployed on a VCN can communicate with variousdifferent endpoints. These endpoints may include endpoints that arehosted by CSPI 700 and endpoints outside CSPI 700. Endpoints hosted byCSPI 700 may include instances in the same VCN or other VCNs, which maybe the customer's VCNs, or VCNs not belonging to the customer.Communications between endpoints hosted by CSPI 700 may be performedover physical network 718. A compute instance may also communicate withendpoints that are not hosted by CSPI 700, or are outside CSPI 700.Examples of these endpoints include endpoints within a customer'son-premise network or data center, or public endpoints accessible over apublic network such as the Internet. Communications with endpointsoutside CSPI 700 may be performed over public networks (e.g., theInternet) (not shown in FIG. 7 ) or private networks (not shown in FIG.7 ) using various communication protocols.

The architecture of CSPI 700 depicted in FIG. 7 is merely an example andis not intended to be limiting. Variations, alternatives, andmodifications are possible in alternative embodiments. For example, insome implementations, CSPI 700 may have more or fewer systems orcomponents than those shown in FIG. 7 , may combine two or more systems,or may have a different configuration or arrangement of systems. Thesystems, subsystems, and other components depicted in FIG. 7 may beimplemented in software (e.g., code, instructions, program) executed byone or more processing units (e.g., processors, cores) of the respectivesystems, using hardware, or combinations thereof. The software may bestored on a non-transitory storage medium (e.g., on a memory device).

FIG. 9 depicts connectivity between a host machine and an NVD forproviding I/O virtualization for supporting multitenancy according tocertain embodiments. As depicted in FIG. 9 , host machine 902 executes ahypervisor 904 that provides a virtualized environment. Host machine 902executes two virtual machine instances, VM1 906 belonging tocustomer/tenant #1 and VM2 908 belonging to customer/tenant #2. Hostmachine 902 comprises a physical NIC 910 that is connected to an NVD 912via link 914. Each of the compute instances is attached to a VNIC thatis executed by NVD 912. In the embodiment in FIG. 9 , VM1 906 isattached to VNIC-VM1 920 and VM2 908 is attached to VNIC-VM2 922.

As shown in FIG. 9 , NIC 910 comprises two logical NICs, logical NIC A916 and logical NIC B 918. Each virtual machine is attached to andconfigured to work with its own logical NIC. For example, VM1 906 isattached to logical NIC A 916 and VM2 908 is attached to logical NIC B918. Even though host machine 902 comprises only one physical NIC 910that is shared by the multiple tenants, due to the logical NICs, eachtenant's virtual machine believes they have their own host machine andNIC.

In certain embodiments, each logical NIC is assigned its own VLAN ID.Thus, a specific VLAN ID is assigned to logical NIC A 916 for Tenant #1and a separate VLAN ID is assigned to logical NIC B 918 for Tenant #2.When a packet is communicated from VM1 906, a tag assigned to Tenant #1is attached to the packet by the hypervisor and the packet is thencommunicated from host machine 902 to NVD 912 over link 914. In asimilar manner, when a packet is communicated from VM2 908, a tagassigned to Tenant #2 is attached to the packet by the hypervisor andthe packet is then communicated from host machine 902 to NVD 912 overlink 914. Accordingly, a packet 924 communicated from host machine 902to NVD 912 has an associated tag 926 that identifies a specific tenantand associated VM. On the NVD, for a packet 924 received from hostmachine 902, the tag 926 associated with the packet is used to determinewhether the packet is to be processed by VNIC-VM1 920 or by VNIC-VM2922. The packet is then processed by the corresponding VNIC. Theconfiguration depicted in FIG. 9 enables each tenant's compute instanceto believe that they own their own host machine and NIC. The setupdepicted in FIG. 9 provides for I/O virtualization for supportingmulti-tenancy.

FIG. 10 depicts a simplified block diagram of a physical network 1000according to certain embodiments. The embodiment depicted in FIG. 10 isstructured as a Clos network. A Clos network is a particular type ofnetwork topology designed to provide connection redundancy whilemaintaining high bisection bandwidth and maximum resource utilization. AClos network is a type of non-blocking, multistage or multi-tieredswitching network, where the number of stages or tiers can be two,three, four, five, etc. The embodiment depicted in FIG. 10 is a 3-tierednetwork comprising tiers 1, 2, and 3. The TOR switches 1004 representTier-0 switches in the Clos network. One or more NVDs are connected tothe TOR switches. Tier-0 switches are also referred to as edge devicesof the physical network. The Tier-0 switches are connected to Tier-1switches, which are also referred to as leaf switches. In the embodimentdepicted in FIG. 10 , a set of “n” Tier-0 TOR switches are connected toa set of “n” Tier-1 switches and together form a pod. Each Tier-0 switchin a pod is interconnected to all the Tier-1 switches in the pod, butthere is no connectivity of switches between pods. In certainimplementations, two pods are referred to as a block. Each block isserved by or connected to a set of “n” Tier-2 switches (sometimesreferred to as spine switches). There can be several blocks in thephysical network topology. The Tier-2 switches are in turn connected to“n” Tier-3 switches (sometimes referred to as super-spine switches).Communication of packets over physical network 1000 is typicallyperformed using one or more Layer-3 communication protocols. Typically,all the layers of the physical network, except for the TORs layer aren-ways redundant thus allowing for high availability. Policies may bespecified for pods and blocks to control the visibility of switches toeach other in the physical network so as to enable scaling of thephysical network.

A feature of a Clos network is that the maximum hop count to reach fromone Tier-0 switch to another Tier-0 switch (or from an NVD connected toa Tier-0-switch to another NVD connected to a Tier-0 switch) is fixed.For example, in a 3-Tiered Clos network at most seven hops are neededfor a packet to reach from one NVD to another NVD, where the source andtarget NVDs are connected to the leaf tier of the Clos network.Likewise, in a 4-tiered Clos network, at most nine hops are needed for apacket to reach from one NVD to another NVD, where the source and targetNVDs are connected to the leaf tier of the Clos network. Thus, a Closnetwork architecture maintains consistent latency throughout thenetwork, which is important for communication within and between datacenters. A Clos topology scales horizontally and is cost effective. Thebandwidth/throughput capacity of the network can be easily increased byadding more switches at the various tiers (e.g., more leaf and spineswitches) and by increasing the number of links between the switches atadjacent tiers.

In certain embodiments, each resource within CSPI is assigned a uniqueidentifier called a Cloud Identifier (CID). This identifier is includedas part of the resource's information and can be used to manage theresource, for example, via a Console or through APIs. An example syntaxfor a CID is:

-   -   ocidl.<RESOURCE TYPE>.<REALM>.[REGION][.FUTURE USE].<UNIQUE ID>        where,        ocidl: The literal string indicating the version of the CID;        resource type: The type of resource (for example, instance,        volume, VCN, subnet, user, group, and so on);        realm: The realm the resource is in. Example values are “c1” for        the commercial realm, “c2” for the Government Cloud realm, or        “c3” for the Federal Government Cloud realm, etc. Each realm may        have its own domain name;        region: The region the resource is in. If the region is not        applicable to the resource, this part might be blank;        future use: Reserved for future use.        unique ID: The unique portion of the ID. The format may vary        depending on the type of resource or service.

FIG. 11 is a block diagram 1100 illustrating an example pattern of anIaaS architecture, according to at least one embodiment. Serviceoperators 1102 can be communicatively coupled to a secure host tenancy1104 that can include a virtual cloud network (VCN) 1106 and a securehost subnet 1108. In some examples, the service operators 1102 may beusing one or more client computing devices, which may be portablehandheld devices (e.g., an iPhone®, cellular telephone, an iPad®,computing tablet, a personal digital assistant (PDA)) or wearabledevices (e.g., a Google Glass® head mounted display), running softwaresuch as Microsoft Windows Mobile®, and/or a variety of mobile operatingsystems such as iOS, Windows Phone, Android, BlackBerry 8, Palm OS, andthe like, and being Internet, e-mail, short message service (SMS),Blackberry®, or other communication protocol enabled. Alternatively, theclient computing devices can be general purpose personal computersincluding, by way of example, personal computers and/or laptop computersrunning various versions of Microsoft Windows®, Apple Macintosh®, and/orLinux operating systems. The client computing devices can be workstationcomputers running any of a variety of commercially-available UNIX® orUNIX-like operating systems, including without limitation the variety ofGNU/Linux operating systems, such as for example, Google Chrome OS.Alternatively, or in addition, client computing devices may be any otherelectronic device, such as a thin-client computer, an Internet-enabledgaming system (e.g., a Microsoft Xbox gaming console with or without aKinect® gesture input device), and/or a personal messaging device,capable of communicating over a network that can access the VCN 1106and/or the Internet.

The VCN 1106 can include a local peering gateway (LPG) 1110 that can becommunicatively coupled to a secure shell (SSH) VCN 1112 via an LPG 1110contained in the SSH VCN 1112. The SSH VCN 1112 can include an SSHsubnet 1114, and the SSH VCN 1112 can be communicatively coupled to acontrol plane VCN 1116 via the LPG 1110 contained in the control planeVCN 1116. Also, the SSH VCN 1112 can be communicatively coupled to adata plane VCN 1118 via an LPG 1110. The control plane VCN 1116 and thedata plane VCN 1118 can be contained in a service tenancy 1119 that canbe owned and/or operated by the IaaS provider.

The control plane VCN 1116 can include a control plane demilitarizedzone (DMZ) tier 1120 that acts as a perimeter network (e.g., portions ofa corporate network between the corporate intranet and externalnetworks). The DMZ-based servers may have restricted responsibilitiesand help keep breaches contained. Additionally, the DMZ tier 1120 caninclude one or more load balancer (LB) subnet(s) 1122, a control planeapp tier 1124 that can include app subnet(s) 1126, a control plane datatier 1128 that can include database (DB) subnet(s) 1130 (e.g., frontendDB subnet(s) and/or backend DB subnet(s)). The LB subnet(s) 1122contained in the control plane DMZ tier 1120 can be communicativelycoupled to the app subnet(s) 1126 contained in the control plane apptier 1124 and an Internet gateway 1134 that can be contained in thecontrol plane VCN 1116, and the app subnet(s) 1126 can becommunicatively coupled to the DB subnet(s) 1130 contained in thecontrol plane data tier 1128 and a service gateway 1136 and a networkaddress translation (NAT) gateway 1138. The control plane VCN 1116 caninclude the service gateway 1136 and the NAT gateway 1138.

The control plane VCN 1116 can include a data plane mirror app tier 1140that can include app subnet(s) 1126. The app subnet(s) 1126 contained inthe data plane mirror app tier 1140 can include a virtual networkinterface controller (VNIC) 1142 that can execute a compute instance1144. The compute instance 1144 can communicatively couple the appsubnet(s) 1126 of the data plane mirror app tier 1140 to app subnet(s)1126 that can be contained in a data plane app tier 1146.

The data plane VCN 1118 can include the data plane app tier 1146, a dataplane DMZ tier 1148, and a data plane data tier 1150. The data plane DMZtier 1148 can include LB subnet(s) 1122 that can be communicativelycoupled to the app subnet(s) 1126 of the data plane app tier 1146 andthe Internet gateway 1134 of the data plane VCN 1118. The app subnet(s)1126 can be communicatively coupled to the service gateway 1136 of thedata plane VCN 1118 and the NAT gateway 1138 of the data plane VCN 1118.The data plane data tier 1150 can also include the DB subnet(s) 1130that can be communicatively coupled to the app subnet(s) 1126 of thedata plane app tier 1146.

The Internet gateway 1134 of the control plane VCN 1116 and of the dataplane VCN 1118 can be communicatively coupled to a metadata managementservice 1152 that can be communicatively coupled to public Internet1154. Public Internet 1154 can be communicatively coupled to the NATgateway 1138 of the control plane VCN 1116 and of the data plane VCN1118. The service gateway 1136 of the control plane VCN 1116 and of thedata plane VCN 1118 can be communicatively couple to cloud services1156.

In some examples, the service gateway 1136 of the control plane VCN 1116or of the data plane VCN 1118 can make application programming interface(API) calls to cloud services 1156 without going through public Internet1154. The API calls to cloud services 1156 from the service gateway 1136can be one-way: the service gateway 1136 can make API calls to cloudservices 1156, and cloud services 1156 can send requested data to theservice gateway 1136. But, cloud services 1156 may not initiate APIcalls to the service gateway 1136.

In some examples, the secure host tenancy 1104 can be directly connectedto the service tenancy 1119, which may be otherwise isolated. The securehost subnet 1108 can communicate with the SSH subnet 1114 through an LPG1110 that may enable two-way communication over an otherwise isolatedsystem. Connecting the secure host subnet 1108 to the SSH subnet 1114may give the secure host subnet 1108 access to other entities within theservice tenancy 1119.

The control plane VCN 1116 may allow users of the service tenancy 1119to set up or otherwise provision desired resources. Desired resourcesprovisioned in the control plane VCN 1116 may be deployed or otherwiseused in the data plane VCN 1118. In some examples, the control plane VCN1116 can be isolated from the data plane VCN 1118, and the data planemirror app tier 1140 of the control plane VCN 1116 can communicate withthe data plane app tier 1146 of the data plane VCN 1118 via VNICs 1142that can be contained in the data plane mirror app tier 1140 and thedata plane app tier 1146.

In some examples, users of the system, or customers, can make requests,for example create, read, update, or delete (CRUD) operations, throughpublic Internet 1154 that can communicate the requests to the metadatamanagement service 1152. The metadata management service 1152 cancommunicate the request to the control plane VCN 1116 through theInternet gateway 1134. The request can be received by the LB subnet(s)1122 contained in the control plane DMZ tier 1120. The LB subnet(s) 1122may determine that the request is valid, and in response to thisdetermination, the LB subnet(s) 1122 can transmit the request to appsubnet(s) 1126 contained in the control plane app tier 1124. If therequest is validated and requires a call to public Internet 1154, thecall to public Internet 1154 may be transmitted to the NAT gateway 1138that can make the call to public Internet 1154. Memory that may bedesired to be stored by the request can be stored in the DB subnet(s)1130.

In some examples, the data plane mirror app tier 1140 can facilitatedirect communication between the control plane VCN 1116 and the dataplane VCN 1118. For example, changes, updates, or other suitablemodifications to configuration may be desired to be applied to theresources contained in the data plane VCN 1118. Via a VNIC 1142, thecontrol plane VCN 1116 can directly communicate with, and can therebyexecute the changes, updates, or other suitable modifications toconfiguration to, resources contained in the data plane VCN 1118.

In some embodiments, the control plane VCN 1116 and the data plane VCN1118 can be contained in the service tenancy 1119. In this case, theuser, or the customer, of the system may not own or operate either thecontrol plane VCN 1116 or the data plane VCN 1118. Instead, the IaaSprovider may own or operate the control plane VCN 1116 and the dataplane VCN 1118, both of which may be contained in the service tenancy1119. This embodiment can enable isolation of networks that may preventusers or customers from interacting with other users', or othercustomers', resources. Also, this embodiment may allow users orcustomers of the system to store databases privately without needing torely on public Internet 1154, which may not have a desired level ofthreat prevention, for storage.

In other embodiments, the LB subnet(s) 1122 contained in the controlplane VCN 1116 can be configured to receive a signal from the servicegateway 1136. In this embodiment, the control plane VCN 1116 and thedata plane VCN 1118 may be configured to be called by a customer of theIaaS provider without calling public Internet 1154. Customers of theIaaS provider may desire this embodiment since database(s) that thecustomers use may be controlled by the IaaS provider and may be storedon the service tenancy 1119, which may be isolated from public Internet1154.

FIG. 12 is a block diagram 1200 illustrating another example pattern ofan IaaS architecture, according to at least one embodiment. Serviceoperators 1202 (e.g. service operators 1102 of FIG. 11 ) can becommunicatively coupled to a secure host tenancy 1204 (e.g. the securehost tenancy 1104 of FIG. 11 ) that can include a virtual cloud network(VCN) 1206 (e.g. the VCN 1106 of FIG. 11 ) and a secure host subnet 1208(e.g. the secure host subnet 1108 of FIG. 11 ). The VCN 1206 can includea local peering gateway (LPG) 1210 (e.g. the LPG 1110 of FIG. 11 ) thatcan be communicatively coupled to a secure shell (SSH) VCN 1212 (e.g.the SSH VCN 1112 of FIG. 11 ) via an LPG 1110 contained in the SSH VCN1212. The SSH VCN 1212 can include an SSH subnet 1214 (e.g. the SSHsubnet 1114 of FIG. 11 ), and the SSH VCN 1212 can be communicativelycoupled to a control plane VCN 1216 (e.g. the control plane VCN 1116 ofFIG. 11 ) via an LPG 1210 contained in the control plane VCN 1216. Thecontrol plane VCN 1216 can be contained in a service tenancy 1219 (e.g.the service tenancy 1119 of FIG. 11 ), and the data plane VCN 1218 (e.g.the data plane VCN 1118 of FIG. 11 ) can be contained in a customertenancy 1221 that may be owned or operated by users, or customers, ofthe system.

The control plane VCN 1216 can include a control plane DMZ tier 1220(e.g. the control plane DMZ tier 1120 of FIG. 11 ) that can include LBsubnet(s) 1222 (e.g. LB subnet(s) 1122 of FIG. 11 ), a control plane apptier 1224 (e.g. the control plane app tier 1124 of FIG. 11 ) that caninclude app subnet(s) 1226 (e.g. app subnet(s) 1126 of FIG. 11 ), acontrol plane data tier 1228 (e.g. the control plane data tier 1128 ofFIG. 11 ) that can include database (DB) subnet(s) 1230 (e.g. similar toDB subnet(s) 1130 of FIG. 11 ). The LB subnet(s) 1222 contained in thecontrol plane DMZ tier 1220 can be communicatively coupled to the appsubnet(s) 1226 contained in the control plane app tier 1224 and anInternet gateway 1234 (e.g. the Internet gateway 1134 of FIG. 11 ) thatcan be contained in the control plane VCN 1216, and the app subnet(s)1226 can be communicatively coupled to the DB subnet(s) 1230 containedin the control plane data tier 1228 and a service gateway 1236 (e.g. theservice gateway of FIG. 11 ) and a network address translation (NAT)gateway 1238 (e.g. the NAT gateway 1138 of FIG. 11 ). The control planeVCN 1216 can include the service gateway 1236 and the NAT gateway 1238.

The control plane VCN 1216 can include a data plane mirror app tier 1240(e.g. the data plane mirror app tier 1140 of FIG. 11 ) that can includeapp subnet(s) 1226. The app subnet(s) 1226 contained in the data planemirror app tier 1240 can include a virtual network interface controller(VNIC) 1242 (e.g. the VNIC of 1142) that can execute a compute instance1244 (e.g. similar to the compute instance 1144 of FIG. 11 ). Thecompute instance 1244 can facilitate communication between the appsubnet(s) 1226 of the data plane mirror app tier 1240 and the appsubnet(s) 1226 that can be contained in a data plane app tier 1246 (e.g.the data plane app tier 1146 of FIG. 11 ) via the VNIC 1242 contained inthe data plane mirror app tier 1240 and the VNIC 1242 contained in thedata plane app tier 1246.

The Internet gateway 1234 contained in the control plane VCN 1216 can becommunicatively coupled to a metadata management service 1252 (e.g. themetadata management service 1152 of FIG. 11 ) that can becommunicatively coupled to public Internet 1254 (e.g. public Internet1154 of FIG. 11 ). Public Internet 1254 can be communicatively coupledto the NAT gateway 1238 contained in the control plane VCN 1216. Theservice gateway 1236 contained in the control plane VCN 1216 can becommunicatively couple to cloud services 1256 (e.g. cloud services 1156of FIG. 11 ).

In some examples, the data plane VCN 1218 can be contained in thecustomer tenancy 1221. In this case, the IaaS provider may provide thecontrol plane VCN 1216 for each customer, and the IaaS provider may, foreach customer, set up a unique compute instance 1244 that is containedin the service tenancy 1219. Each compute instance 1244 may allowcommunication between the control plane VCN 1216, contained in theservice tenancy 1219, and the data plane VCN 1218 that is contained inthe customer tenancy 1221. The compute instance 1244 may allowresources, that are provisioned in the control plane VCN 1216 that iscontained in the service tenancy 1219, to be deployed or otherwise usedin the data plane VCN 1218 that is contained in the customer tenancy1221.

In other examples, the customer of the IaaS provider may have databasesthat live in the customer tenancy 1221. In this example, the controlplane VCN 1216 can include the data plane mirror app tier 1240 that caninclude app subnet(s) 1226. The data plane mirror app tier 1240 canreside in the data plane VCN 1218, but the data plane mirror app tier1240 may not live in the data plane VCN 1218. That is, the data planemirror app tier 1240 may have access to the customer tenancy 1221, butthe data plane mirror app tier 1240 may not exist in the data plane VCN1218 or be owned or operated by the customer of the IaaS provider. Thedata plane mirror app tier 1240 may be configured to make calls to thedata plane VCN 1218 but may not be configured to make calls to anyentity contained in the control plane VCN 1216. The customer may desireto deploy or otherwise use resources in the data plane VCN 1218 that areprovisioned in the control plane VCN 1216, and the data plane mirror apptier 1240 can facilitate the desired deployment, or other usage ofresources, of the customer.

In some embodiments, the customer of the IaaS provider can apply filtersto the data plane VCN 1218. In this embodiment, the customer candetermine what the data plane VCN 1218 can access, and the customer mayrestrict access to public Internet 1254 from the data plane VCN 1218.The IaaS provider may not be able to apply filters or otherwise controlaccess of the data plane VCN 1218 to any outside networks or databases.Applying filters and controls by the customer onto the data plane VCN1218, contained in the customer tenancy 1221, can help isolate the dataplane VCN 1218 from other customers and from public Internet 1254.

In some embodiments, cloud services 1256 can be called by the servicegateway 1236 to access services that may not exist on public Internet1254, on the control plane VCN 1216, or on the data plane VCN 1218. Theconnection between cloud services 1256 and the control plane VCN 1216 orthe data plane VCN 1218 may not be live or continuous. Cloud services1256 may exist on a different network owned or operated by the IaaSprovider. Cloud services 1256 may be configured to receive calls fromthe service gateway 1236 and may be configured to not receive calls frompublic Internet 1254. Some cloud services 1256 may be isolated fromother cloud services 1256, and the control plane VCN 1216 may beisolated from cloud services 1256 that may not be in the same region asthe control plane VCN 1216. For example, the control plane VCN 1216 maybe located in “Region 1,” and cloud service “Deployment 11,” may belocated in Region 1 and in “Region 2.” If a call to Deployment 11 ismade by the service gateway 1236 contained in the control plane VCN 1216located in Region 1, the call may be transmitted to Deployment 11 inRegion 1. In this example, the control plane VCN 1216, or Deployment 11in Region 1, may not be communicatively coupled to, or otherwise incommunication with, Deployment 11 in Region 2.

FIG. 13 is a block diagram 1300 illustrating another example pattern ofan IaaS architecture, according to at least one embodiment. Serviceoperators 1302 (e.g. service operators 1102 of FIG. 11 ) can becommunicatively coupled to a secure host tenancy 1304 (e.g. the securehost tenancy 1104 of FIG. 11 ) that can include a virtual cloud network(VCN) 1306 (e.g. the VCN 1106 of FIG. 11 ) and a secure host subnet 1308(e.g. the secure host subnet 1108 of FIG. 11 ). The VCN 1306 can includean LPG 1310 (e.g. the LPG 1110 of FIG. 11 ) that can be communicativelycoupled to an SSH VCN 1312 (e.g. the SSH VCN 1112 of FIG. 11 ) via anLPG 1310 contained in the SSH VCN 1312. The SSH VCN 1312 can include anSSH subnet 1314 (e.g. the SSH subnet 1114 of FIG. 11 ), and the SSH VCN1312 can be communicatively coupled to a control plane VCN 1316 (e.g.the control plane VCN 1116 of FIG. 11 ) via an LPG 1310 contained in thecontrol plane VCN 1316 and to a data plane VCN 1318 (e.g. the data plane1118 of FIG. 11 ) via an LPG 1310 contained in the data plane VCN 1318.The control plane VCN 1316 and the data plane VCN 1318 can be containedin a service tenancy 1319 (e.g. the service tenancy 1119 of FIG. 11 ).

The control plane VCN 1316 can include a control plane DMZ tier 1320(e.g. the control plane DMZ tier 1120 of FIG. 11 ) that can include loadbalancer (LB) subnet(s) 1322 (e.g. LB subnet(s) 1122 of FIG. 11 ), acontrol plane app tier 1324 (e.g. the control plane app tier 1124 ofFIG. 11 ) that can include app subnet(s) 1326 (e.g. similar to appsubnet(s) 1126 of FIG. 11 ), a control plane data tier 1328 (e.g. thecontrol plane data tier 1128 of FIG. 11 ) that can include DB subnet(s)1330. The LB subnet(s) 1322 contained in the control plane DMZ tier 1320can be communicatively coupled to the app subnet(s) 1326 contained inthe control plane app tier 1324 and to an Internet gateway 1334 (e.g.the Internet gateway 1134 of FIG. 11 ) that can be contained in thecontrol plane VCN 1316, and the app subnet(s) 1326 can becommunicatively coupled to the DB subnet(s) 1330 contained in thecontrol plane data tier 1328 and to a service gateway 1336 (e.g. theservice gateway of FIG. 11 ) and a network address translation (NAT)gateway 1338 (e.g. the NAT gateway 1138 of FIG. 11 ). The control planeVCN 1316 can include the service gateway 1336 and the NAT gateway 1338.

The data plane VCN 1318 can include a data plane app tier 1346 (e.g. thedata plane app tier 1146 of FIG. 11 ), a data plane DMZ tier 1348 (e.g.the data plane DMZ tier 1148 of FIG. 11 ), and a data plane data tier1350 (e.g. the data plane data tier 1150 of FIG. 11 ). The data planeDMZ tier 1348 can include LB subnet(s) 1322 that can be communicativelycoupled to trusted app subnet(s) 1360 and untrusted app subnet(s) 1362of the data plane app tier 1346 and the Internet gateway 1334 containedin the data plane VCN 1318. The trusted app subnet(s) 1360 can becommunicatively coupled to the service gateway 1336 contained in thedata plane VCN 1318, the NAT gateway 1338 contained in the data planeVCN 1318, and DB subnet(s) 1330 contained in the data plane data tier1350. The untrusted app subnet(s) 1362 can be communicatively coupled tothe service gateway 1336 contained in the data plane VCN 1318 and DBsubnet(s) 1330 contained in the data plane data tier 1350. The dataplane data tier 1350 can include DB subnet(s) 1330 that can becommunicatively coupled to the service gateway 1336 contained in thedata plane VCN 1318.

The untrusted app subnet(s) 1362 can include one or more primary VNICs1364(1)-(N) that can be communicatively coupled to tenant virtualmachines (VMs) 1366(1)-(N). Each tenant VM 1366(1)-(N) can becommunicatively coupled to a respective app subnet 1367(1)-(N) that canbe contained in respective container egress VCNs 1368(1)-(N) that can becontained in respective customer tenancies 1370(1)-(N). Respectivesecondary VNICs 1372(1)-(N) can facilitate communication between theuntrusted app subnet(s) 1362 contained in the data plane VCN 1318 andthe app subnet contained in the container egress VCNs 1368(1)-(N). Eachcontainer egress VCNs 1368(1)-(N) can include a NAT gateway 1338 thatcan be communicatively coupled to public Internet 1354 (e.g. publicInternet 1154 of FIG. 11 ).

The Internet gateway 1334 contained in the control plane VCN 1316 andcontained in the data plane VCN 1318 can be communicatively coupled to ametadata management service 1352 (e.g. the metadata management system1152 of FIG. 11 ) that can be communicatively coupled to public Internet1354. Public Internet 1354 can be communicatively coupled to the NATgateway 1338 contained in the control plane VCN 1316 and contained inthe data plane VCN 1318. The service gateway 1336 contained in thecontrol plane VCN 1316 and contained in the data plane VCN 1318 can becommunicatively couple to cloud services 1356.

In some embodiments, the data plane VCN 1318 can be integrated withcustomer tenancies 1370. This integration can be useful or desirable forcustomers of the IaaS provider in some cases such as a case that maydesire support when executing code. The customer may provide code to runthat may be destructive, may communicate with other customer resources,or may otherwise cause undesirable effects. In response to this, theIaaS provider may determine whether to run code given to the IaaSprovider by the customer.

In some examples, the customer of the IaaS provider may grant temporarynetwork access to the IaaS provider and request a function to beattached to the data plane tier app 1346. Code to run the function maybe executed in the VMs 1366(1)-(N), and the code may not be configuredto run anywhere else on the data plane VCN 1318. Each VM 1366(1)-(N) maybe connected to one customer tenancy 1370. Respective containers1371(1)-(N) contained in the VMs 1366(1)-(N) may be configured to runthe code. In this case, there can be a dual isolation (e.g., thecontainers 1371(1)-(N) running code, where the containers 1371(1)-(N)may be contained in at least the VM 1366(1)-(N) that are contained inthe untrusted app subnet(s) 1362), which may help prevent incorrect orotherwise undesirable code from damaging the network of the IaaSprovider or from damaging a network of a different customer. Thecontainers 1371(1)-(N) may be communicatively coupled to the customertenancy 1370 and may be configured to transmit or receive data from thecustomer tenancy 1370. The containers 1371(1)-(N) may not be configuredto transmit or receive data from any other entity in the data plane VCN1318. Upon completion of running the code, the IaaS provider may kill orotherwise dispose of the containers 1371(1)-(N).

In some embodiments, the trusted app subnet(s) 1360 may run code thatmay be owned or operated by the IaaS provider. In this embodiment, thetrusted app subnet(s) 1360 may be communicatively coupled to the DBsubnet(s) 1330 and be configured to execute CRUD operations in the DBsubnet(s) 1330. The untrusted app subnet(s) 1362 may be communicativelycoupled to the DB subnet(s) 1330, but in this embodiment, the untrustedapp subnet(s) may be configured to execute read operations in the DBsubnet(s) 1330. The containers 1371(1)-(N) that can be contained in theVM 1366(1)-(N) of each customer and that may run code from the customermay not be communicatively coupled with the DB subnet(s) 1330.

In other embodiments, the control plane VCN 1316 and the data plane VCN1318 may not be directly communicatively coupled. In this embodiment,there may be no direct communication between the control plane VCN 1316and the data plane VCN 1318. However, communication can occur indirectlythrough at least one method. An LPG 1310 may be established by the IaaSprovider that can facilitate communication between the control plane VCN1316 and the data plane VCN 1318. In another example, the control planeVCN 1316 or the data plane VCN 1318 can make a call to cloud services1356 via the service gateway 1336. For example, a call to cloud services1356 from the control plane VCN 1316 can include a request for a servicethat can communicate with the data plane VCN 1318.

FIG. 14 is a block diagram 1400 illustrating another example pattern ofan IaaS architecture, according to at least one embodiment. Serviceoperators 1402 (e.g. service operators 1102 of FIG. 11 ) can becommunicatively coupled to a secure host tenancy 1404 (e.g. the securehost tenancy 1104 of FIG. 11 ) that can include a virtual cloud network(VCN) 1406 (e.g. the VCN 1106 of FIG. 11 ) and a secure host subnet 1408(e.g. the secure host subnet 1108 of FIG. 11 ). The VCN 1406 can includean LPG 1410 (e.g. the LPG 1110 of FIG. 11 ) that can be communicativelycoupled to an SSH VCN 1412 (e.g. the SSH VCN 1112 of FIG. 11 ) via anLPG 1410 contained in the SSH VCN 1412. The SSH VCN 1412 can include anSSH subnet 1414 (e.g. the SSH subnet 1114 of FIG. 11 ), and the SSH VCN1412 can be communicatively coupled to a control plane VCN 1416 (e.g.the control plane VCN 1116 of FIG. 11 ) via an LPG 1410 contained in thecontrol plane VCN 1416 and to a data plane VCN 1418 (e.g. the data plane1118 of FIG. 11 ) via an LPG 1410 contained in the data plane VCN 1418.The control plane VCN 1416 and the data plane VCN 1418 can be containedin a service tenancy 1419 (e.g. the service tenancy 1119 of FIG. 11 ).

The control plane VCN 1416 can include a control plane DMZ tier 1420(e.g. the control plane DMZ tier 1120 of FIG. 11 ) that can include LBsubnet(s) 1422 (e.g. LB subnet(s) 1122 of FIG. 11 ), a control plane apptier 1424 (e.g. the control plane app tier 1124 of FIG. 11 ) that caninclude app subnet(s) 1426 (e.g. app subnet(s) 1126 of FIG. 11 ), acontrol plane data tier 1428 (e.g. the control plane data tier 1128 ofFIG. 11 ) that can include DB subnet(s) 1430 (e.g. DB subnet(s) 1330 ofFIG. 13 ). The LB subnet(s) 1422 contained in the control plane DMZ tier1420 can be communicatively coupled to the app subnet(s) 1426 containedin the control plane app tier 1424 and to an Internet gateway 1434 (e.g.the Internet gateway 1134 of FIG. 11 ) that can be contained in thecontrol plane VCN 1416, and the app subnet(s) 1426 can becommunicatively coupled to the DB subnet(s) 1430 contained in thecontrol plane data tier 1428 and to a service gateway 1436 (e.g. theservice gateway of FIG. 11 ) and a network address translation (NAT)gateway 1438 (e.g. the NAT gateway 1138 of FIG. 11 ). The control planeVCN 1416 can include the service gateway 1436 and the NAT gateway 1438.

The data plane VCN 1418 can include a data plane app tier 1446 (e.g. thedata plane app tier 1146 of FIG. 11 ), a data plane DMZ tier 1448 (e.g.the data plane DMZ tier 1148 of FIG. 11 ), and a data plane data tier1450 (e.g. the data plane data tier 1150 of FIG. 11 ). The data planeDMZ tier 1448 can include LB subnet(s) 1422 that can be communicativelycoupled to trusted app subnet(s) 1460 (e.g. trusted app subnet(s) 1360of FIG. 13 ) and untrusted app subnet(s) 1462 (e.g. untrusted appsubnet(s) 1362 of FIG. 13 ) of the data plane app tier 1446 and theInternet gateway 1434 contained in the data plane VCN 1418. The trustedapp subnet(s) 1460 can be communicatively coupled to the service gateway1436 contained in the data plane VCN 1418, the NAT gateway 1438contained in the data plane VCN 1418, and DB subnet(s) 1430 contained inthe data plane data tier 1450. The untrusted app subnet(s) 1462 can becommunicatively coupled to the service gateway 1436 contained in thedata plane VCN 1418 and DB subnet(s) 1430 contained in the data planedata tier 1450. The data plane data tier 1450 can include DB subnet(s)1430 that can be communicatively coupled to the service gateway 1436contained in the data plane VCN 1418.

The untrusted app subnet(s) 1462 can include primary VNICs 1464(1)-(N)that can be communicatively coupled to tenant virtual machines (VMs)1466(1)-(N) residing within the untrusted app subnet(s) 1462. Eachtenant VM 1466(1)-(N) can run code in a respective container1467(1)-(N), and be communicatively coupled to an app subnet 1426 thatcan be contained in a data plane app tier 1446 that can be contained ina container egress VCN 1468. Respective secondary VNICs 1472(1)-(N) canfacilitate communication between the untrusted app subnet(s) 1462contained in the data plane VCN 1418 and the app subnet contained in thecontainer egress VCN 1468. The container egress VCN can include a NATgateway 1438 that can be communicatively coupled to public Internet 1454(e.g. public Internet 1154 of FIG. 11 ).

The Internet gateway 1434 contained in the control plane VCN 1416 andcontained in the data plane VCN 1418 can be communicatively coupled to ametadata management service 1452 (e.g. the metadata management system1152 of FIG. 11 ) that can be communicatively coupled to public Internet1454. Public Internet 1454 can be communicatively coupled to the NATgateway 1438 contained in the control plane VCN 1416 and contained inthe data plane VCN 1418. The service gateway 1436 contained in thecontrol plane VCN 1416 and contained in the data plane VCN 1418 can becommunicatively couple to cloud services 1456.

In some examples, the pattern illustrated by the architecture of blockdiagram 1400 of FIG. 14 may be considered an exception to the patternillustrated by the architecture of block diagram 1300 of FIG. 13 and maybe desirable for a customer of the IaaS provider if the IaaS providercannot directly communicate with the customer (e.g., a disconnectedregion). The respective containers 1467(1)-(N) that are contained in theVMs 1466(1)-(N) for each customer can be accessed in real-time by thecustomer. The containers 1467(1)-(N) may be configured to make calls torespective secondary VNICs 1472(1)-(N) contained in app subnet(s) 1426of the data plane app tier 1446 that can be contained in the containeregress VCN 1468. The secondary VNICs 1472(1)-(N) can transmit the callsto the NAT gateway 1438 that may transmit the calls to public Internet1454. In this example, the containers 1467(1)-(N) that can be accessedin real-time by the customer can be isolated from the control plane VCN1416 and can be isolated from other entities contained in the data planeVCN 1418. The containers 1467(1)-(N) may also be isolated from resourcesfrom other customers.

In other examples, the customer can use the containers 1467(1)-(N) tocall cloud services 1456. In this example, the customer may run code inthe containers 1467(1)-(N) that requests a service from cloud services1456. The containers 1467(1)-(N) can transmit this request to thesecondary VNICs 1472(1)-(N) that can transmit the request to the NATgateway that can transmit the request to public Internet 1454. PublicInternet 1454 can transmit the request to LB subnet(s) 1422 contained inthe control plane VCN 1416 via the Internet gateway 1434. In response todetermining the request is valid, the LB subnet(s) can transmit therequest to app subnet(s) 1426 that can transmit the request to cloudservices 1456 via the service gateway 1436.

It should be appreciated that IaaS architectures 1100, 1200, 1300, 1400depicted in the figures may have other components than those depicted.Further, the embodiments shown in the figures are only some examples ofa cloud infrastructure system that may incorporate an embodiment of thedisclosure. In some other embodiments, the IaaS systems may have more orfewer components than shown in the figures, may combine two or morecomponents, or may have a different configuration or arrangement ofcomponents.

In certain embodiments, the IaaS systems described herein may include asuite of applications, middleware, and database service offerings thatare delivered to a customer in a self-service, subscription-based,elastically scalable, reliable, highly available, and secure manner. Anexample of such an IaaS system is the Oracle Cloud Infrastructure (OCI)provided by the present assignee.

FIG. 15 illustrates an example computer system 1500, in which variousembodiments may be implemented. The system 1500 may be used to implementany of the computer systems described above. As shown in the figure,computer system 1500 includes a processing unit 1504 that communicateswith a number of peripheral subsystems via a bus subsystem 1502. Theseperipheral subsystems may include a processing acceleration unit 1506,an I/O subsystem 1508, a storage sub system 1518 and a communicationssub system 1524. Storage sub system 1518 includes tangiblecomputer-readable storage media 1522 and a system memory 1510.

Bus subsystem 1502 provides a mechanism for letting the variouscomponents and subsystems of computer system 1500 communicate with eachother as intended. Although bus subsystem 1502 is shown schematically asa single bus, alternative embodiments of the bus subsystem may utilizemultiple buses. Bus subsystem 1502 may be any of several types of busstructures including a memory bus or memory controller, a peripheralbus, and a local bus using any of a variety of bus architectures. Forexample, such architectures may include an Industry StandardArchitecture (ISA) bus, Micro Channel Architecture (MCA) bus, EnhancedISA (EISA) bus, Video Electronics Standards Association (VESA) localbus, and Peripheral Component Interconnect (PCI) bus, which can beimplemented as a Mezzanine bus manufactured to the IEEE P1386.1standard.

Processing unit 1504, which can be implemented as one or more integratedcircuits (e.g., a conventional microprocessor or microcontroller),controls the operation of computer system 1500. One or more processorsmay be included in processing unit 1504. These processors may includesingle core or multicore processors. In certain embodiments, processingunit 1504 may be implemented as one or more independent processing units1532 and/or 1534 with single or multicore processors included in eachprocessing unit. In other embodiments, processing unit 1504 may also beimplemented as a quad-core processing unit formed by integrating twodual-core processors into a single chip.

In various embodiments, processing unit 1504 can execute a variety ofprograms in response to program code and can maintain multipleconcurrently executing programs or processes. At any given time, some orall of the program code to be executed can be resident in processor(s)1504 and/or in storage subsystem 1518. Through suitable programming,processor(s) 1504 can provide various functionalities described above.Computer system 1500 may additionally include a processing accelerationunit 1506, which can include a digital signal processor (DSP), aspecial-purpose processor, and/or the like.

I/O subsystem 1508 may include user interface input devices and userinterface output devices. User interface input devices may include akeyboard, pointing devices such as a mouse or trackball, a touchpad ortouch screen incorporated into a display, a scroll wheel, a click wheel,a dial, a button, a switch, a keypad, audio input devices with voicecommand recognition systems, microphones, and other types of inputdevices. User interface input devices may include, for example, motionsensing and/or gesture recognition devices such as the Microsoft Kinect®motion sensor that enables users to control and interact with an inputdevice, such as the Microsoft Xbox® 360 game controller, through anatural user interface using gestures and spoken commands. Userinterface input devices may also include eye gesture recognition devicessuch as the Google Glass® blink detector that detects eye activity(e.g., ‘blinking’ while taking pictures and/or making a menu selection)from users and transforms the eye gestures as input into an input device(e.g., Google Glass®). Additionally, user interface input devices mayinclude voice recognition sensing devices that enable users to interactwith voice recognition systems (e.g., Siri® navigator), through voicecommands.

User interface input devices may also include, without limitation, threedimensional (3D) mice, joysticks or pointing sticks, gamepads andgraphic tablets, and audio/visual devices such as speakers, digitalcameras, digital camcorders, portable media players, webcams, imagescanners, fingerprint scanners, barcode reader 3D scanners, 3D printers,laser rangefinders, and eye gaze tracking devices. Additionally, userinterface input devices may include, for example, medical imaging inputdevices such as computed tomography, magnetic resonance imaging,position emission tomography, medical ultrasonography devices. Userinterface input devices may also include, for example, audio inputdevices such as MIDI keyboards, digital musical instruments and thelike.

User interface output devices may include a display subsystem, indicatorlights, or non-visual displays such as audio output devices, etc. Thedisplay subsystem may be a cathode ray tube (CRT), a flat-panel device,such as that using a liquid crystal display (LCD) or plasma display, aprojection device, a touch screen, and the like. In general, use of theterm “output device” is intended to include all possible types ofdevices and mechanisms for outputting information from computer system1500 to a user or other computer. For example, user interface outputdevices may include, without limitation, a variety of display devicesthat visually convey text, graphics and audio/video information such asmonitors, printers, speakers, headphones, automotive navigation systems,plotters, voice output devices, and modems.

Computer system 1500 may comprise a storage subsystem 1518 thatcomprises software elements, shown as being currently located within asystem memory 1510. System memory 1510 may store program instructionsthat are loadable and executable on processing unit 1504, as well asdata generated during the execution of these programs.

Depending on the configuration and type of computer system 1500, systemmemory 1510 may be volatile (such as random access memory (RAM)) and/ornon-volatile (such as read-only memory (ROM), flash memory, etc.) TheRAM typically contains data and/or program modules that are immediatelyaccessible to and/or presently being operated and executed by processingunit 1504. In some implementations, system memory 1510 may includemultiple different types of memory, such as static random access memory(SRAM) or dynamic random access memory (DRAM). In some implementations,a basic input/output system (BIOS), containing the basic routines thathelp to transfer information between elements within computer system1500, such as during start-up, may typically be stored in the ROM. Byway of example, and not limitation, system memory 1510 also illustratesapplication programs 1512, which may include client applications, Webbrowsers, mid-tier applications, relational database management systems(RDBMS), etc., program data 1514, and an operating system 1516. By wayof example, operating system 1516 may include various versions ofMicrosoft Windows®, Apple Macintosh®, and/or Linux operating systems, avariety of commercially-available UNIX® or UNIX-like operating systems(including without limitation the variety of GNU/Linux operatingsystems, the Google Chrome® OS, and the like) and/or mobile operatingsystems such as iOS, Windows® Phone, Android® OS, BlackBerry® 15 OS, andPalm® OS operating systems.

Storage subsystem 1518 may also provide a tangible computer-readablestorage medium for storing the basic programming and data constructsthat provide the functionality of some embodiments. Software (programs,code modules, instructions) that when executed by a processor providethe functionality described above may be stored in storage subsystem1518. These software modules or instructions may be executed byprocessing unit 1504. Storage subsystem 1518 may also provide arepository for storing data used in accordance with the presentdisclosure.

Storage subsystem 1500 may also include a computer-readable storagemedia reader 1520 that can further be connected to computer-readablestorage media 1522. Together and, optionally, in combination with systemmemory 1510, computer-readable storage media 1522 may comprehensivelyrepresent remote, local, fixed, and/or removable storage devices plusstorage media for temporarily and/or more permanently containing,storing, transmitting, and retrieving computer-readable information.

Computer-readable storage media 1522 containing code, or portions ofcode, can also include any appropriate media known or used in the art,including storage media and communication media, such as but not limitedto, volatile and non-volatile, removable and non-removable mediaimplemented in any method or technology for storage and/or transmissionof information. This can include tangible computer-readable storagemedia such as RAM, ROM, electronically erasable programmable ROM(EEPROM), flash memory or other memory technology, CD-ROM, digitalversatile disk (DVD), or other optical storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or other tangible computer readable media. This can also includenontangible computer-readable media, such as data signals, datatransmissions, or any other medium which can be used to transmit thedesired information and which can be accessed by computing system 1500.

By way of example, computer-readable storage media 1522 may include ahard disk drive that reads from or writes to non-removable, nonvolatilemagnetic media, a magnetic disk drive that reads from or writes to aremovable, nonvolatile magnetic disk, and an optical disk drive thatreads from or writes to a removable, nonvolatile optical disk such as aCD ROM, DVD, and Blu-Ray® disk, or other optical media.Computer-readable storage media 1522 may include, but is not limited to,Zip® drives, flash memory cards, universal serial bus (USB) flashdrives, secure digital (SD) cards, DVD disks, digital video tape, andthe like. Computer-readable storage media 1522 may also include,solid-state drives (SSD) based on non-volatile memory such asflash-memory based SSDs, enterprise flash drives, solid state ROM, andthe like, SSDs based on volatile memory such as solid state RAM, dynamicRAM, static RAM, DRAM-based SSDs, magnetoresistive RAM (MRAM) SSDs, andhybrid SSDs that use a combination of DRAM and flash memory based SSDs.The disk drives and their associated computer-readable media may providenon-volatile storage of computer-readable instructions, data structures,program modules, and other data for computer system 1500.

Communications subsystem 1524 provides an interface to other computersystems and networks. Communications subsystem 1524 serves as aninterface for receiving data from and transmitting data to other systemsfrom computer system 1500. For example, communications subsystem 1524may enable computer system 1500 to connect to one or more devices viathe Internet. In some embodiments communications subsystem 1524 caninclude radio frequency (RF) transceiver components for accessingwireless voice and/or data networks (e.g., using cellular telephonetechnology, advanced data network technology, such as 3G, 4G or EDGE(enhanced data rates for global evolution), WiFi (IEEE 802.11 familystandards, or other mobile communication technologies, or anycombination thereof), global positioning system (GPS) receivercomponents, and/or other components. In some embodiments communicationssubsystem 1524 can provide wired network connectivity (e.g., Ethernet)in addition to or instead of a wireless interface.

In some embodiments, communications subsystem 1524 may also receiveinput communication in the form of structured and/or unstructured datafeeds 1526, event streams 1528, event updates 1530, and the like onbehalf of one or more users who may use computer system 1500.

By way of example, communications subsystem 1524 may be configured toreceive data feeds 1526 in real-time from users of social networksand/or other communication services such as Twitter® feeds, Facebook®updates, web feeds such as Rich Site Summary (RSS) feeds, and/orreal-time updates from one or more third party information sources.

Additionally, communications subsystem 1524 may also be configured toreceive data in the form of continuous data streams, which may includeevent streams 1528 of real-time events and/or event updates 1530, thatmay be continuous or unbounded in nature with no explicit end. Examplesof applications that generate continuous data may include, for example,sensor data applications, financial tickers, network performancemeasuring tools (e.g. network monitoring and traffic managementapplications), clickstream analysis tools, automobile trafficmonitoring, and the like.

Communications subsystem 1524 may also be configured to output thestructured and/or unstructured data feeds 1526, event streams 1528,event updates 1530, and the like to one or more databases that may be incommunication with one or more streaming data source computers coupledto computer system 1500.

Computer system 1500 can be one of various types, including a handheldportable device (e.g., an iPhone® cellular phone, an iPad® computingtablet, a PDA), a wearable device (e.g., a Google Glass® head mounteddisplay), a PC, a workstation, a mainframe, a kiosk, a server rack, orany other data processing system.

Due to the ever-changing nature of computers and networks, thedescription of computer system 1500 depicted in the figure is intendedonly as a specific example. Many other configurations having more orfewer components than the system depicted in the figure are possible.For example, customized hardware might also be used and/or particularelements might be implemented in hardware, firmware, software (includingapplets), or a combination. Further, connection to other computingdevices, such as network input/output devices, may be employed. Based onthe disclosure and teachings provided herein, a person of ordinary skillin the art will appreciate other ways and/or methods to implement thevarious embodiments.

Although specific embodiments have been described, variousmodifications, alterations, alternative constructions, and equivalentsare also encompassed within the scope of the disclosure. Embodiments arenot restricted to operation within certain specific data processingenvironments, but are free to operate within a plurality of dataprocessing environments. Additionally, although embodiments have beendescribed using a particular series of transactions and steps, it shouldbe apparent to those skilled in the art that the scope of the presentdisclosure is not limited to the described series of transactions andsteps. Various features and aspects of the above-described embodimentsmay be used individually or jointly.

Further, while embodiments have been described using a particularcombination of hardware and software, it should be recognized that othercombinations of hardware and software are also within the scope of thepresent disclosure. Embodiments may be implemented only in hardware, oronly in software, or using combinations thereof. The various processesdescribed herein can be implemented on the same processor or differentprocessors in any combination. Accordingly, where components or modulesare described as being configured to perform certain operations, suchconfiguration can be accomplished, e.g., by designing electroniccircuits to perform the operation, by programming programmableelectronic circuits (such as microprocessors) to perform the operation,or any combination thereof. Processes can communicate using a variety oftechniques including but not limited to conventional techniques forinter process communication, and different pairs of processes may usedifferent techniques, or the same pair of processes may use differenttechniques at different times.

The specification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense. It will, however, beevident that additions, subtractions, deletions, and other modificationsand changes may be made thereunto without departing from the broaderspirit and scope as set forth in the claims. Thus, although specificdisclosure embodiments have been described, these are not intended to belimiting. Various modifications and equivalents are within the scope ofthe following claims.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the disclosed embodiments (especially in thecontext of the following claims) are to be construed to cover both thesingular and the plural, unless otherwise indicated herein or clearlycontradicted by context. The terms “comprising,” “having,” “including,”and “containing” are to be construed as open-ended terms (i.e., meaning“including, but not limited to,”) unless otherwise noted. The term“connected” is to be construed as partly or wholly contained within,attached to, or joined together, even if there is something intervening.Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein and eachseparate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate embodiments and does not pose alimitation on the scope of the disclosure unless otherwise claimed. Nolanguage in the specification should be construed as indicating anynon-claimed element as essential to the practice of the disclosure.

Disjunctive language such as the phrase “at least one of X, Y, or Z,”unless specifically stated otherwise, is intended to be understoodwithin the context as used in general to present that an item, term,etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y,and/or Z). Thus, such disjunctive language is not generally intended to,and should not, imply that certain embodiments require at least one ofX, at least one of Y, or at least one of Z to each be present.

Preferred embodiments of this disclosure are described herein, includingthe best mode known for carrying out the disclosure. Variations of thosepreferred embodiments may become apparent to those of ordinary skill inthe art upon reading the foregoing description. Those of ordinary skillshould be able to employ such variations as appropriate and thedisclosure may be practiced otherwise than as specifically describedherein. Accordingly, this disclosure includes all modifications andequivalents of the subject matter recited in the claims appended heretoas permitted by applicable law. Moreover, any combination of theabove-described elements in all possible variations thereof isencompassed by the disclosure unless otherwise indicated herein.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

In the foregoing specification, aspects of the disclosure are describedwith reference to specific embodiments thereof, but those skilled in theart will recognize that the disclosure is not limited thereto. Variousfeatures and aspects of the above-described disclosure may be usedindividually or jointly. Further, embodiments can be utilized in anynumber of environments and applications beyond those described hereinwithout departing from the broader spirit and scope of thespecification. The specification and drawings are, accordingly, to beregarded as illustrative rather than restrictive.

What is claimed is:
 1. A method comprising: executing, by a securenetwork connectivity system implemented in a cloud service provider, asecure network connectivity service for enabling secure private networkconnectivity between an on-premise network associated with a customer ofthe cloud service provider and a virtual cloud network (VCN) hosted bythe cloud service provider for the customer, the secure networkconnectivity system comprising a virtual overlay network comprising aset of one or more computing nodes; registering, by the secure networkconnectivity system, an external resource residing in the on-premisenetwork as an external endpoint in the virtual cloud network, theexternal endpoint identified by an Internet Protocol (IP) address in thevirtual cloud network; creating, by a first computing node in the set ofone or more computing nodes in the secure network connectivity system,an external resource representation for the external endpoint in thevirtual cloud network, creating the external resource representationcomprising: creating, by the first computing node in the set of one ormore computing nodes in the secure network connectivity system, avirtual network interface card (VNIC); and assigning, by the firstcomputing node in the set of one or more computing nodes in the securenetwork connectivity system, the Internet Protocol (IP) addressassociated with the external endpoint to the virtual network interfacecard (VNIC); transmitting, by the first computing node in the securenetwork connectivity system, configuration information corresponding tothe virtual network interface card (VNIC) for the external resourcerepresentation to an agent configured in the on-premise networkassociated with the customer; receiving, by a second computing node inthe set of one or more computing nodes in the secure networkconnectivity system, a request for querying information associated witha resource residing in the virtual cloud network (VCN) associated withthe customer, the query being transmitted by the external resourceresiding in the on-premise network, and the external resource beingprovisioned with a logical interface; establishing, by the secondcomputing node in the secure network connectivity system, a connectionbetween the logical interface provisioned for the external resourceresiding in the on-premise network and the virtual network interfacecard (VNIC) created for the external resource representation in thevirtual cloud network; transmitting, by the second computing node in thesecure network connectivity system, the request received from theexternal resource residing in the on-premise network to the resourceresiding in the virtual cloud network via the virtual network interfacecard (VNIC) created for the external resource representation in thevirtual cloud network using the established connection; obtaining, bythe second computing node in the secure network connectivity system, aresult corresponding to the request via the established connection; andtransmitting, by the second computing node in the secure networkconnectivity system, the result to the external resource via the virtualnetwork interface card (VNIC) created for the external resourcerepresentation in the virtual cloud network using the establishedconnection.
 2. The method of claim 1, wherein the agent in theon-premise network is configured to establish a secure Virtual PrivateNetwork (VPN) connection between the external resource residing in theon-premise network and the set of one or more computing nodes comprisingthe secure network connectivity system.
 3. The method of claim 1,wherein the agent is configured to provision the logical interface forthe external resource residing in the on-premise network based at leastin part on the configuration information corresponding to the virtualnetwork interface card (VNIC) for the external resource representation.4. The method of claim 3, wherein provisioning the logical interface forthe external resource comprises, assigning, by the agent, the virtualInternet Protocol (IP) address of the virtual network interface card(VNIC) for the external resource representation to the logicalinterface.
 5. The method of claim 3, wherein the configurationinformation corresponding to the virtual network interface card (VNIC)for the external resource representation comprises the virtual InternetProtocol (IP) address of the virtual network interface card (VNIC), afully qualified domain name associated with a computing instanceassociated with the virtual network interface card (VNIC) and a cloudidentifier of the virtual cloud network associated with the customer. 6.The method of claim 5, further comprising establishing, by the secondcomputing node, the connection between the logical interface provisionedfor the external resource residing in the on-premise network and thevirtual network interface card created for the external resourcerepresentation in the virtual cloud network via the agent residing inthe on-premise network.
 7. The method of claim 6, wherein transmitting,by the second computing node, the request to the resource residing inthe virtual cloud network via the established connection comprises:translating, by the second computing node, the physical IP addressassociated with the external resource to the virtual IP addressassociated with the virtual network interface card for the externalresource representation in the virtual cloud network associated with thecustomer; and transmitting, by the second computing node, the request tothe virtual IP address associated with the virtual network interfacecard.
 8. The method of claim 1, further comprising enabling, by thesecure network connectivity system, a creation of an external siterepresentation of the on-premise network associated with the customer,wherein the external site representation is a logical representation ofthe on-premise network and identified by an external site identifier anda customer identifier.
 9. The method of claim 8, wherein the externalresource is registered in the external site representation.
 10. Themethod of claim 9, further comprising establishing, by the secondcomputing node in the secure network connectivity system, the connectionbetween the logical interface provisioned for the external resourceresiding in the external site representation and the virtual networkinterface card created for the external resource representation in thevirtual cloud network.
 11. The method of claim 1, wherein the externalresource is a database, an application, or a compute instance residingin the on-premise network.
 12. A secure network connectivity systemimplemented in a cloud service provider for enabling secure privatenetwork connectivity between an on-premise network associated with acustomer of the cloud service provider and a virtual cloud network (VCN)hosted by the cloud service provider for the customer, the securenetwork connectivity system comprising a virtual overlay networkcomprising a set of one or more computing nodes, a computing node in theset of computing nodes comprising: a memory; and one or more processorsconfigured to perform processing, the processing comprising:registering, by the secure network connectivity system, an externalresource residing in the on-premise network as an external endpoint inthe virtual cloud network, the external endpoint identified by anInternet Protocol (IP) address in the virtual cloud network; creating,by a first computing node in the set of one or more computing nodes inthe secure network connectivity system, an external resourcerepresentation for the external endpoint in the virtual cloud network,creating the external resource representation comprising: creating, bythe first computing node in the set of one or more computing nodes inthe secure network connectivity system, a virtual network interface card(VNIC); and assigning, by the first computing node in the set of one ormore computing nodes in the secure network connectivity system, theInternet Protocol (IP) address associated with the external endpoint tothe virtual network interface card (VNIC); transmitting, by the firstcomputing node in the secure network connectivity system, configurationinformation corresponding to the virtual network interface card (VNIC)for the external resource representation to an agent configured in theon-premise network associated with the customer; receiving, by a secondcomputing node in the set of one or more computing nodes in the securenetwork connectivity system, a request for querying informationassociated with a resource residing in the virtual cloud network (VCN)associated with the customer, the query being transmitted by theexternal resource residing in the on-premise network, and the externalresource being provisioned with a logical interface; establishing, bythe second computing node in the secure network connectivity system, aconnection between the logical interface provisioned for the externalresource residing in the on-premise network and the virtual networkinterface card (VNIC) created for the external resource representationin the virtual cloud network; transmitting, by the second computing nodein the secure network connectivity system, the request received from theexternal resource residing in the on-premise network to the resourceresiding in the virtual cloud network via the virtual network interfacecard (VNIC) created for the external resource representation in thevirtual cloud network using the established connection; obtaining, bythe second computing node in the secure network connectivity system, aresult corresponding to the request via the established connection andtransmitting, by the second computing node in the secure networkconnectivity system, the result to the external resource via the virtualnetwork interface card (VNIC) created for the external resourcerepresentation in the virtual cloud network using the establishedconnection.
 13. The system of claim 12, wherein the agent in theon-premise network is configured to establish a secure Virtual PrivateNetwork (VPN) connection between the external resource residing in theon-premise network and the set of one or more computing nodes comprisingthe secure network connectivity system.
 14. The system of claim 13wherein the agent is configured to provision the logical interface forthe external resource residing in the on-premise network based at leastin part on the configuration information corresponding to the virtualnetwork interface card (VNIC) for the external resource representation.15. The system of claim 14, wherein provisioning the logical interfacefor the external resource comprises, assigning, by the agent, thevirtual Internet Protocol (IP) address of the virtual network interfacecard (VNIC) for the external resource representation to the logicalinterface.
 16. The system of claim 15, wherein the configurationinformation corresponding to the virtual network interface card (VNIC)for the external resource representation comprises the virtual InternetProtocol (IP) address of the virtual network interface card (VNIC), afully qualified domain name associated with a computing instanceassociated with the virtual network interface card (VNIC) and a cloudidentifier of the virtual cloud network associated with the customer.17. A non-transitory computer-readable medium having program code thatis stored thereon, the program code executable by one or more processingdevices for performing operations comprising: registering an externalresource residing in the on-premise network as an external endpoint inthe virtual cloud network, the external endpoint identified by anInternet Protocol (IP) address in the virtual cloud network; creating anexternal resource representation for the external endpoint in thevirtual cloud network, creating the external resource representationcomprising: creating a virtual network interface card (VNIC); andassigning the Internet Protocol (IP) address associated with theexternal endpoint to the virtual network interface card (VNIC);transmitting configuration information corresponding to the virtualnetwork interface card (VNIC) for the external resource representationto an agent configured in the on-premise network associated with thecustomer; receiving a request for querying information associated with aresource residing in the virtual cloud network (VCN) associated with thecustomer, the query being transmitted by the external resource residingin the on-premise network, and the external resource being provisionedwith a logical interface; establishing a connection between the logicalinterface provisioned for the external resource residing in theon-premise network and the virtual network interface card (VNIC) createdfor the external resource representation in the virtual cloud network;transmitting the request received from the external resource residing inthe on-premise network to the resource residing in the virtual cloudnetwork via the virtual network interface card (VNIC) created for theexternal resource representation in the virtual cloud network using theestablished connection; obtaining a result corresponding to the requestvia the established connection; and transmitting the result to theexternal resource via the virtual network interface card (VNIC) createdfor the external resource representation in the virtual cloud networkusing the established connection.
 18. The non-transitorycomputer-readable medium of claim 17, wherein the agent is configured toprovision the logical interface for the external resource residing inthe on-premise network based at least in part on the configurationinformation corresponding to the virtual network interface card (VNIC)for the external resource representation.
 19. The non-transitorycomputer-readable medium of claim 18, wherein provisioning the logicalinterface for the external resource comprises, assigning, by the agent,the virtual Internet Protocol (IP) address of the virtual networkinterface card (VNIC) for the external resource representation to thelogical interface.
 20. The non-transitory computer-readable medium ofclaim 17, wherein the configuration information corresponding to thevirtual network interface card (VNIC) for the external resourcerepresentation comprises the virtual Internet Protocol (IP) address ofthe virtual network interface card (VNIC), a fully qualified domain nameassociated with a computing instance associated with the virtual networkinterface card (VNIC) and a cloud identifier of the virtual cloudnetwork associated with the customer.